oct 16, 18 notes. add unit tests with utest, and bisection root finding methods

Makefile

@@ -1,9 +1,12 @@
-TEST_SRC := test/main.c
 SRC_DIR := src
 OBJ_DIR := build
 BIN_DIR := dist
 LIB_DIR := lib
 
+TEST_SRC_DIR := test
+TEST_SRC := $(wildcard $(TEST_SRC_DIR)/*.c)
+TEST_OBJ := $(TEST_SRC:$(TEST_SRC_DIR)/%.c=$(OBJ_DIR)/%.o)
+
 TEST_EXE := $(BIN_DIR)/lizfcm.test
 EXE      := $(BIN_DIR)/lizfcm
 LIBRARY  := $(LIB_DIR)/lizfcm.a
@@ -18,20 +21,26 @@ LDFLAGS  := -lm
 
 all: $(TEST_EXE)
 
-$(TEST_EXE): $(BIN_DIR) | $(LIBRARY)
+$(TEST_EXE): $(TEST_OBJ) $(LIBRARY) | $(BIN_DIR)
-	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $(TEST_SRC) $(LIBRARY) -o $@
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $^ -o $@
 
 $(LIBRARY): $(OBJ) | $(LIB_DIR)
 	ar rcs $(LIBRARY) $(OBJ_DIR)/*.o
 	ranlib $(LIBRARY)
 
+$(OBJ_DIR)/%.o: $(TEST_SRC_DIR)/%.c | $(OBJ_DIR)
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c $< -o $@
+
 $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c | $(OBJ_DIR)
 	$(CC) $(CPPFLAGS) $(CFLAGS) -c $< -o $@
 
 $(BIN_DIR) $(OBJ_DIR) $(LIB_DIR):
 	mkdir -p $@
 
+print-%  : ; @echo $* = $($*)
+
 clean:
 	@$(RM) -r $(BIN_DIR) $(OBJ_DIR) $(LIB_DIR)
 
 -include $(OBJ:.o=.d)
+-include $(TEST_OBJ:.o=.d)

homeworks/hw-4.tex

@@ -1,4 +1,4 @@
-% Created 2023-10-13 Fri 20:54
+% Created 2023-10-13 Fri 21:11
 % Intended LaTeX compiler: pdflatex
 \documentclass[11pt]{article}
 \usepackage[utf8]{inputenc}
@@ -29,17 +29,17 @@
 \setlength\parindent{0pt}
 
 \section{Question 1}
-\label{sec:org0ce46da}
+\label{sec:orgf7348d4}
 See the attached LIZFCM Software Manual.
 
 \section{Question 2, 3, 4}
-\label{sec:org0794d50}
+\label{sec:orgaf52510}
 \begin{center}
 \includegraphics[width=350px]{./img/make_run.png}
 \end{center}
 
 \section{Question 5}
-\label{sec:orgf7b84cc}
+\label{sec:orgd0fe6e8}
 \begin{center}
 \includegraphics[width=350px]{./img/test_routine_1.png}
 \end{center}
@@ -49,22 +49,22 @@ See the attached LIZFCM Software Manual.
 \end{center}
 
 \section{Question 6}
-\label{sec:orgee1884d}
+\label{sec:org9e2023c}
 See the LIZFCM Software Manual.
 
 \section{Question 7}
-\label{sec:org6f86e09}
+\label{sec:org6c11571}
 See \texttt{src/matrix.c -> lu\_decomp, fsubst, bsubst, solve\_matrix}
 
 \section{Question 8}
-\label{sec:orga79c31e}
+\label{sec:org9ba7792}
 See \texttt{test/main.c -> lines 109 - 113} in correspondence to the run in Question 5
 
 \section{Question 9}
-\label{sec:org5b1b74d}
+\label{sec:org3cff888}
 See \texttt{test/main.c -> lines 118 - 121} in correspondence to the run in Question 5
 
 \section{Question 10}
-\label{sec:org7409683}
+\label{sec:org522eabc}
 See the TOC on the first page of the LIZFCM Software Manual.
 \end{document}

inc/lizfcm.h

@@ -27,6 +27,7 @@ extern double linf_distance(Array_double *v1, Array_double *v2);
 extern Array_double *copy_vector(Array_double *v1);
 extern void free_vector(Array_double *v);
 extern void format_vector_into(Array_double *v, char *s);
+extern int vector_equal(Array_double *a, Array_double *b);
 
 extern Matrix_double *put_identity_diagonal(Matrix_double *m);
 extern Matrix_double **lu_decomp(Matrix_double *m);
@@ -37,7 +38,16 @@ extern Array_double *m_dot_v(Matrix_double *m, Array_double *v);
 extern Matrix_double *copy_matrix(Matrix_double *m);
 extern void free_matrix(Matrix_double *m);
 extern void format_matrix_into(Matrix_double *m, char *s);
+extern int matrix_equal(Matrix_double *a, Matrix_double *b);
 
 extern Line *least_squares_lin_reg(Array_double *x, Array_double *y);
 
+extern double *find_ivt_range(double (*f)(double), double start_x, double delta,
+                              size_t max_steps);
+extern double bisect_find_root(double (*f)(double), double a, double b,
+                               double tolerance, size_t max_iterations);
+extern double bisect_find_root_with_error_assumption(double (*f)(double),
+                                                     double a, double b,
+                                                     double tolerance);
+
 #endif // LIZFCM_H

inc/macros.h

@@ -52,4 +52,7 @@
 #define c_max(x, y) (((x) >= (y)) ? (x) : (y))
 #define c_min(x, y) (((x) <= (y)) ? (x) : (y))
 
+#define true 1;
+#define false 0;
+
 #endif // MACROS_H

notes/Oct-16.org

@@ -0,0 +1,77 @@
+Find x \in R st f(x) = 0
+
+if f(x^*) = 0 then define x^* = g(x^*) = x^* + f(x^*)
+
+Suppose we approximate x^* by x_0. Then Using the fixed point equations:
+
+x_1 = g(x_0) = x_0 + f(x_0)
+x_2 = g(g_1) \cdots x_{k+1} = g(x_k)
+
+This generates a sequence of approximations to x^*
+
+{X_k} \rightarrow x^*
+
+The algorithm is: Given f(x), x_0, compute x_{k+1} = g(x_k), k = 0, 1, 2, \cdots
+= x_k + f(x_k)
+
+Examples for g(x)
+
+1. x_{k+1} = x_k + f(x_k)
+2. x_{k+1} = x_k - f(x_k)
+3. x_{k+1} = x_k - mf(x_k)
+4. x_{k+q} = s_k - sin(f(x_k))
+
+x^* = root of f
+y^* = solution of y^* = g(y^*)
+
+| x^* - y^* | = x^* - (y^* - f(y^*))
+|x_{k+1} - x^*  | = | g(x_k) - g(x^*) |
+ = |g(x^*) + g'(x^k)(x_k - x^*) + \cdots) - g(x^*)|
+ = |g'(x^*)(x_k - x^*) + hot|
+ \leq | g'(x^*)(x_k - x^*)| + (pos val)
+ \leq |g'(x^*)| (|x_k - x^*|)
+
+\Rightarrow |x_{k+1} - x^*| \leq |g'(x^*)| \cdot |x_k - x^*|
+
+For this to converge, we need |g'(x^*)| \lt 1
+
+* Example
+f(x) = xe^{-x}
+
+Then x^* = 0
+
+If we construct g(x) = 10x + xe^-x
+
+Then g'(x) = 10 + (e^-x - xe^-x) \Rightarrow g'(x) = 10 + e^0 - 0 = 11 (this wouldn't converge)n
+
+However if g(x)) = x - (xe^-x), g'(x) = 1 - (e^-x - xe^-x) \Rightarrow g'(x^*) = 0
+
+Then assume x_0 = 1/10
+Then x_1 = g(x_0) = 1/10 - 1/10(e^{-1/10})
+\cdots
+
+* More General, Robust Algorithm
+** Theorem: Intermediate Value Theorem
+Suppose that f(x) is a continuous function on [a, b] then
+
+\lim_{x -> x_0} (f(x)) = f(x_0)
+
+For all x_0 \in (a, b) and at the endpoints:
+
+\lim_{a^+} f(x) = f(a)
+\lim_{x -> b^-} f(x) = f(b)
+
+Then if s is a number between f(a) and f(b), there exists a point c \in (a, b) such that f(c) = s.
+
+To use this to ensure there is a root, we just take evaluations f(a) and f(b) that cross 0
+
+So the condition we construct is:
+f(a) \cdot f(b) \lt 0
+
+** Next Step: compute the midpoint of [a, b]
+c = 1/2 (a + b)
+
+do binary search on c by taking this midpoint and ensuring f(a) \cdot f(c) \lt 0 or f(c) \cdot f(b) \lt 0 is met,
+choosing the correct interval
+
+

notes/Oct-18.org

@@ -0,0 +1,18 @@
+Error Analysis Of Bisection Root Finding:
+
+e_0 \le b - a = b_0 - a_0
+e_1 \le b_1 - a_1 = 1/2(b_0 - a_0)
+e_2 \le b_2 - a_2 = 1/2(b_1 - a_1) = (1/2)^2(b_0 - a_0)
+e_k \le b_k - a_k = 1/2(b_{k-1} - a_{k-1}) = \cdots = (1/2)^k (b_0 - a_0)
+
+
+e_k \le (1/2)^k (b_0 - a_0) = tolerance
+\Rightarrow log(1/2^k) + log(b_0 - a_0) = log(tolerance)
+\Rightarrow k log(1/2) + log(tolerance) - log(b_0 - a_0)
+\Rightarrow k log(1/2) = log(tolerance / (b_0 - a_0))
+\Rightarrow k \ge log(tolerance / (b_0 - a_0)) / log(1/2)
+
+The Bisection Method applied to an interval [a, b] for a continous function will reduce the error
+each time through by at least one half.
+
+| x_{k+1} - x_k | \le 1/2|x_k - x^* |

src/matrix.c

@@ -37,7 +37,7 @@ Matrix_double **lu_decomp(Matrix_double *m) {
   Matrix_double *u = copy_matrix(m);
   Matrix_double *l_empt = InitMatrixWithSize(double, m->rows, m->cols, 0.0);
   Matrix_double *l = put_identity_diagonal(l_empt);
-  free(l_empt);
+  free_matrix(l_empt);
 
   Matrix_double **u_l = malloc(sizeof(Matrix_double *) * 2);
 
@@ -140,3 +140,14 @@ void format_matrix_into(Matrix_double *m, char *s) {
   }
   strcat(s, "\n");
 }
+
+int matrix_equal(Matrix_double *a, Matrix_double *b) {
+  if (a->cols != b->cols || a->rows != b->rows)
+    return false;
+
+  for (size_t y = 0; y < a->rows; ++y)
+    if (!vector_equal(a->data[y], b->data[y])) {
+      return false;
+    }
+  return true;
+}

src/roots.c

@@ -0,0 +1,46 @@
+#include "lizfcm.h"
+#include <assert.h>
+#include <math.h>
+
+// f is well defined at start_x + delta*n for all n on the integer range [0,
+// max_steps]
+double *find_ivt_range(double (*f)(double), double start_x, double delta,
+                       size_t max_steps) {
+  double *range = malloc(sizeof(double) * 2);
+
+  double a = start_x;
+
+  while (f(a) * f(start_x) >= 0 && max_steps-- > 0)
+    a += delta;
+
+  if (max_steps == 0 && f(a) * f(start_x) > 0)
+    return NULL;
+
+  range[0] = start_x;
+  range[1] = a + delta;
+  return range;
+}
+
+// f is continuous on [a, b]
+double bisect_find_root(double (*f)(double), double a, double b,
+                        double tolerance, size_t max_iterations) {
+  assert(a <= b);
+  // guarantee there's a root somewhere between a and b by IVT
+  assert(f(a) * f(b) < 0);
+
+  double c = (1.0 / 2) * (a + b);
+  if (b - a < tolerance || max_iterations == 0)
+    return c;
+  if (f(a) * f(c) < 0)
+    return bisect_find_root(f, a, c, tolerance, max_iterations - 1);
+  return bisect_find_root(f, c, b, tolerance, max_iterations - 1);
+}
+
+double bisect_find_root_with_error_assumption(double (*f)(double), double a,
+                                              double b, double tolerance) {
+  assert(a <= b);
+
+  uint64_t max_iterations =
+      (uint64_t)ceil((log(tolerance) - log(b - a)) / log(1 / 2.0));
+  return bisect_find_root(f, a, b, tolerance, max_iterations);
+}

src/vector.c

@@ -115,3 +115,14 @@ double sum_v(Array_double *v) {
     sum += v->data[i];
   return sum;
 }
+
+int vector_equal(Array_double *a, Array_double *b) {
+  if (a->size != b->size)
+    return false;
+
+  for (size_t i = 0; i < a->size; ++i) {
+    if (a->data[i] != b->data[i])
+      return false;
+  }
+  return true;
+}

test/approx_derivative.t.c

@@ -0,0 +1,32 @@
+#include "lizfcm.test.h"
+
+double f(double x) { return x * x; }
+
+double f_prime(double x) { return 2 * x; }
+
+double H = 0.0001;
+double ACCEPTED_DERIVATIVE_ERROR = 0.0001;
+
+UTEST(derivative, central) {
+  double a = 3.0;
+  double expected = f_prime(a);
+  double f_prime_x = central_derivative_at(&f, a, H);
+
+  EXPECT_NEAR(expected, f_prime_x, ACCEPTED_DERIVATIVE_ERROR);
+}
+
+UTEST(derivative, forward) {
+  double a = 3.0;
+  double expected = f_prime(a);
+  double f_prime_x = forward_derivative_at(&f, a, H);
+
+  EXPECT_NEAR(expected, f_prime_x, ACCEPTED_DERIVATIVE_ERROR);
+}
+
+UTEST(derivative, backward) {
+  double a = 3.0;
+  double expected = f_prime(a);
+  double f_prime_x = backward_derivative_at(&f, a, H);
+
+  EXPECT_NEAR(expected, f_prime_x, ACCEPTED_DERIVATIVE_ERROR);
+}

test/lin.t.c

@@ -0,0 +1,20 @@
+#include "lizfcm.test.h"
+
+UTEST(Lin, least_squares_lin_reg_perfect) {
+  Array_double *x = InitArray(double, {0, 1, 2, 3, 4});
+  Array_double *y = InitArray(double, {1, 2, 3, 4, 5});
+
+  Line *line = least_squares_lin_reg(x, y);
+
+  EXPECT_EQ(line->m, 1.0);
+  EXPECT_EQ(line->a, 1.0);
+}
+
+UTEST(Lin, least_squares_lin_reg_estimate) {
+  Array_double *x = InitArray(double, {1, 2, 3, 4, 5, 6, 7});
+  Array_double *y = InitArray(double, {0.5, 3, 2, 3.5, 5, 6, 7.5});
+
+  Line *line = least_squares_lin_reg(x, y);
+
+  EXPECT_NEAR(line->m, 1.0, 0.2);
+}

test/lizfcm.test.h

@@ -0,0 +1,7 @@
+#include "lizfcm.h"
+#include "utest.h"
+
+#ifndef LIZFCM_TEST_H
+#define LIZFCM_TEST_H
+
+#endif // LIZFCM_TEST_H

test/maceps.t.c

@@ -0,0 +1,18 @@
+#include "lizfcm.test.h"
+#include <math.h>
+
+UTEST(maceps, smaceps) {
+  float epsilon = smaceps();
+  float one = 1.0;
+  float approx_one = one + epsilon;
+
+  EXPECT_LE(approx_one - one, 0);
+}
+
+UTEST(maceps, dmaceps) {
+  double epsilon = dmaceps();
+  double one = 1.0;
+  double approx_one = one + epsilon;
+
+  EXPECT_LE(approx_one - one, 0);
+}

test/main.c

@@ -1,124 +1,5 @@
-#include "lizfcm.h"
+#include "lizfcm.test.h"
-#include <math.h>
-#include <stdio.h>
-#include <stdlib.h>
 
-double f(double x) { return (x - 1) / (x + 1); }
+UTEST(basic, unit_tests) { ASSERT_TRUE(1); }
 
-int main() {
+UTEST_MAIN();
-  char s[2048];
-
-  printf("Basic Routines\n");
-  printf("smaceps(): %.10e\n", smaceps());
-  printf("dmaceps(): %.10e\n", dmaceps());
-  printf("========\n");
-
-  printf("Norm, Distance\n");
-  Array_double *v = InitArray(double, {3, 1, -4});
-  strcpy(s, "");
-  format_vector_into(v, s);
-  printf("v: %s", s);
-
-  Array_double *w = InitArray(double, {-2, 7, 1});
-  strcpy(s, "");
-  format_vector_into(w, s);
-  printf("w: %s", s);
-
-  printf("l1_norm(v): %f\n", l1_norm(v));
-  printf("l2_norm(v): %f\n", l2_norm(v));
-  printf("linf_norm(v): %f\n", linf_norm(v));
-  printf("l1_dist(v, w): %f\n", l1_distance(v, w));
-  printf("l2_dist(v, w): %f\n", l2_distance(v, w));
-  printf("linf_dist(v, w): %f\n", linf_distance(v, w));
-  printf("========\n");
-
-  double h = 0.001;
-  printf("Derivative Approxs\n");
-  printf("f(x) = (x-1)/(x+1)\n");
-  printf("approx f'(1) w/ c.d.: %f\n", central_derivative_at(&f, 1, h));
-  printf("approx f'(1) w/ fw.d.: %f\n", forward_derivative_at(&f, 1, h));
-  printf("approx f'(1) w/ bw.d.: %f\n", backward_derivative_at(&f, 1, h));
-  printf("========\n");
-  printf("Least Squares\n");
-
-  v = InitArray(double, {1, 2, 3, 4, 5});
-  strcpy(s, "");
-  format_vector_into(v, s);
-  printf("v: %s", s);
-  w = InitArray(double, {2, 3, 4, 5, 6});
-  strcpy(s, "");
-  format_vector_into(w, s);
-  printf("w: %s", s);
-
-  Line *line = least_squares_lin_reg(v, w);
-  printf("least_squares_lin_reg(v, w): (%f)x + %f\n", line->m, line->a);
-  v = InitArray(double, {1, 2, 3, 4, 5, 6, 7});
-  strcpy(s, "");
-  format_vector_into(v, s);
-  printf("v: %s", s);
-  w = InitArray(double, {0.5, 3, 2, 3.5, 5, 6, 7.5});
-  strcpy(s, "");
-  format_vector_into(w, s);
-  printf("w: %s", s);
-
-  line = least_squares_lin_reg(v, w);
-  printf("least_squares_lin_reg(v, w): (%f)x + %f\n", line->m, line->a);
-  free(line);
-  printf("========\n");
-
-  printf("LU Decomp\n");
-  uint32_t n = 10;
-  Matrix_double *a = InitMatrixWithSize(double, n, n, 0.0);
-  for (int i = 0; i < n; i++) {
-    for (int j = 0; j < n; j++)
-      a->data[i]->data[j] = (100 - rand() % 200);
-  }
-  strcpy(s, "");
-  format_matrix_into(a, s);
-  printf("a = %s", s);
-
-  uint32_t solution = 1;
-  Array_double *y = InitArrayWithSize(double, n, (double)solution);
-  Array_double *b = m_dot_v(a, y); // q8 steps
-  Matrix_double **u_l = lu_decomp(a);
-  Matrix_double *u = u_l[0];
-  Matrix_double *l = u_l[1];
-
-  strcpy(s, "");
-  format_matrix_into(u, s);
-  printf("u = %s", s);
-  strcpy(s, "");
-  format_matrix_into(l, s);
-  printf("l = %s", s);
-  strcpy(s, "");
-  format_vector_into(b, s);
-  printf("(after following q8) b = %s", s);
-  printf("========\n");
-  printf("Forward / Backward Substitution Solution to ax=b\n");
-
-  Array_double *b_fsub = fsubst(l, b);
-  strcpy(s, "");
-  format_vector_into(b_fsub, s);
-  printf("b_fsub: %s", s);
-
-  Array_double *x_bsub = bsubst(u, b_fsub);
-  strcpy(s, "");
-  format_vector_into(x_bsub, s);
-  printf("x_bsub: %s", s);
-
-  Array_double *x_solve_matrix = solve_matrix(a, b);
-  free_vector(b);
-  strcpy(s, "");
-  format_vector_into(x_solve_matrix, s);
-  printf("\\--> == x_solve_matrix: %s", s);
-
-  free_vector(b_fsub);
-  free_vector(x_solve_matrix);
-
-  printf("Verifications\n");
-  for (size_t i = 0; i < x_bsub->size; i++)
-    printf("in row %zu, solution = %f, true value err=%.10e\n", i,
-           x_bsub->data[i], fabs(x_bsub->data[i] - solution));
-
-  return 0;
-}

test/matrix.t.c

@@ -0,0 +1,96 @@
+#include "lizfcm.test.h"
+
+UTEST(matrix, free) {
+  Matrix_double *m = InitMatrixWithSize(double, 8, 8, 0.0);
+  uint64_t data_addr = (uint64_t)(m->data);
+  free_matrix(m);
+  EXPECT_NE(data_addr, (uint64_t)(m->data));
+}
+
+UTEST(matrix, put_identity_diagonal) {
+  Matrix_double *m = InitMatrixWithSize(double, 8, 8, 0.0);
+  Matrix_double *ident = put_identity_diagonal(m);
+
+  for (size_t y = 0; y < m->rows; ++y)
+    for (size_t x = 0; x < m->cols; ++x)
+      EXPECT_EQ(ident->data[y]->data[x], x == y ? 1.0 : 0.0);
+
+  free_matrix(m);
+  free_matrix(ident);
+}
+
+UTEST(matrix, copy) {
+  Matrix_double *m = InitMatrixWithSize(double, 8, 8, 0.0);
+  Matrix_double *ident = put_identity_diagonal(m);
+
+  Matrix_double *copy = copy_matrix(ident);
+
+  EXPECT_TRUE(matrix_equal(ident, copy));
+
+  free_matrix(m);
+  free_matrix(ident);
+  free_matrix(copy);
+}
+
+UTEST(matrix, m_dot_v) {
+  Matrix_double *m = InitMatrixWithSize(double, 8, 8, 0.0);
+  Matrix_double *ident = put_identity_diagonal(m);
+
+  Array_double *x = InitArray(double, {1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0});
+  Array_double *dotted = m_dot_v(ident, x);
+
+  EXPECT_TRUE(vector_equal(dotted, x));
+
+  free_matrix(m);
+  free_matrix(ident);
+  free_vector(x);
+  free_vector(dotted);
+}
+
+UTEST(matrix, lu_decomp) {
+  Matrix_double *m = InitMatrixWithSize(double, 8, 8, 0.0);
+  for (size_t y = 0; y < m->rows; ++y) {
+    for (size_t x = 0; x < m->cols; ++x)
+      m->data[y]->data[x] = x == y ? 5.0 : (5.0 - rand() % 10 + 1);
+  }
+
+  Matrix_double **ul = lu_decomp(m);
+  Matrix_double *u = ul[0];
+  Matrix_double *l = ul[1];
+  for (int y = 0; y < m->rows; y++) {
+    for (size_t x = 0; x < c_max(y - 1, 0); x++) {
+      double u_yx = u->data[y]->data[x];
+      EXPECT_NEAR(u_yx, 0.0, 0.0001);
+    }
+
+    for (size_t x = c_min(m->cols, y + 1); x < m->cols; ++x) {
+      double l_yx = l->data[y]->data[x];
+      EXPECT_NEAR(l_yx, 0.0, 0.0001);
+    }
+  }
+
+  free_matrix(m);
+  free_matrix(l);
+  free_matrix(u);
+  free(ul);
+}
+
+UTEST(matrix, solve_matrix) {
+  Matrix_double *m = InitMatrixWithSize(double, 8, 8, 0.0);
+  for (size_t y = 0; y < m->rows; ++y) {
+    for (size_t x = 0; x < m->cols; ++x)
+      m->data[y]->data[x] = x == y ? 10.0 : (5.0 - rand() % 10 + 1);
+  }
+
+  Array_double *b = InitArray(double, {1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0});
+  Array_double *solution = solve_matrix(m, b);
+
+  for (size_t y = 0; y < m->rows; y++) {
+    double dot = v_dot_v(m->data[y], solution);
+    EXPECT_NEAR(b->data[y], dot, 0.0001);
+  }
+
+  free_matrix(m);
+  free_vector(b);
+  free_vector(solution);
+}

test/roots.t.c

@@ -0,0 +1,17 @@
+#include "lizfcm.test.h"
+#include <stdio.h>
+
+double g(double x) { return x * x - 9; }
+
+UTEST(ivt, find_interval) {
+  double *range = find_ivt_range(&g, -100.0, 1.0, 200);
+  EXPECT_LT(g(range[0]) * g(range[1]), 0);
+
+  free(range);
+}
+
+UTEST(root, bisection_with_error_assumption) {
+  double root = bisect_find_root_with_error_assumption(&g, -5, 0, 0.01);
+
+  EXPECT_NEAR(-3, root, 0.01);
+}

test/vector.t.c

@@ -0,0 +1,93 @@
+#include "lizfcm.test.h"
+#include <math.h>
+
+UTEST(vector, copy_vector) {
+  Array_double *v = InitArray(double, {3, 1, -4});
+  Array_double *w = copy_vector(v);
+  EXPECT_TRUE(vector_equal(v, w));
+
+  free_vector(v);
+  free_vector(w);
+}
+
+UTEST(vector, free_vector) {
+  Array_double *v = InitArray(double, {3, 1, -4});
+  uint64_t arr_addr = (uint64_t)v->data;
+  free_vector(v);
+  EXPECT_NE((uint64_t)v->data, arr_addr);
+}
+
+UTEST(vector, sum_vector) {
+  Array_double *v = InitArray(double, {3, 1, -4});
+  EXPECT_EQ(0.0, sum_v(v));
+  free_vector(v);
+}
+
+UTEST(vector, add_v) {
+  Array_double *a = InitArray(double, {1.0, 3.0, -4.0});
+  Array_double *b = InitArray(double, {2.0, -1.0, 0});
+  Array_double *expected_sum = InitArray(double, {3.0, 2.0, -4.0});
+  Array_double *sum = add_v(a, b);
+
+  EXPECT_TRUE(vector_equal(sum, expected_sum));
+
+  free_vector(a);
+  free_vector(b);
+  free_vector(expected_sum);
+  free_vector(sum);
+}
+
+UTEST(vector, minus_v) {
+  Array_double *a = InitArray(double, {1.0, 3.0, -4.0});
+  Array_double *b = InitArray(double, {2.0, -1.0, 0});
+  Array_double *expected_sub = InitArray(double, {-1.0, 4.0, -4.0});
+  Array_double *sub = minus_v(a, b);
+
+  EXPECT_TRUE(vector_equal(sub, expected_sub));
+
+  free_vector(a);
+  free_vector(b);
+  free_vector(expected_sub);
+  free_vector(sub);
+}
+
+UTEST(vector, scale_v) {
+  double factor = 3.0;
+  Array_double *a = InitArray(double, {1.0, 3.0, -4.0});
+  Array_double *expected_scaled = InitArray(double, {3.0, 9.0, -12.0});
+  Array_double *scaled = scale_v(a, factor);
+
+  EXPECT_TRUE(vector_equal(scaled, expected_scaled));
+
+  free_vector(a);
+  free_vector(expected_scaled);
+  free_vector(scaled);
+}
+
+UTEST(vector, l1_norm) {
+  Array_double *v = InitArray(double, {3, 1, -4});
+  EXPECT_EQ(l1_norm(v), 8.0);
+  free_vector(v);
+}
+
+UTEST(vector, l2_norm) {
+  Array_double *v = InitArray(double, {3, 1, -4});
+  EXPECT_EQ(l2_norm(v), sqrt(3 * 3 + 1 * 1 + 4 * 4));
+  free_vector(v);
+}
+
+UTEST(vector, linf_norm) {
+  Array_double *v = InitArray(double, {3, 1, -4});
+  EXPECT_EQ(linf_norm(v), c_max(c_max(3.0, 1.0), -4.0));
+  free_vector(v);
+}
+
+UTEST(vector, vector_distance) {
+  Array_double *v = InitArray(double, {3, 1, -4});
+  Array_double *w = InitArray(double, {3, 1, -4});
+  Array_double *minus = minus_v(v, w);
+  EXPECT_EQ(vector_distance(v, w, &l2_norm), l2_norm(minus));
+  free_vector(v);
+  free_vector(w);
+  free_vector(minus);
+}