Rename to log_sum_exp and simplify approx_equal

tests/Test/src/basic/test_basic_logsumexp.birch → tests/Test/src/basic/test_basic_log_sum_exp.birch

@@ -3,7 +3,7 @@
  * Test log-sum-exp implementations in `log_sum_exp` and
  * `resample_reduce`.
  */
-program test_basic_logsumexp() {
+program test_basic_log_sum_exp() {
  /* generate random weights */
  w:Real[100];
  for n in 1..100 {
@@ -13,29 +13,29 @@ program test_basic_logsumexp() {
  /* compare with common two-pass algorithm */
  let y <- log_sum_exp_twopass(w);
  let ess <- exp(2*y - log_sum_exp_twopass(2*w));
- if !check_ess_logsumexp(w, ess, y) {
+ if !check_ess_log_sum_exp(w, ess, y) {
  exit(1);
  }
 
  /* check overflow */
  w <- w + 1000.0;
  y <- log_sum_exp_twopass(w);
  ess <- exp(2*y - log_sum_exp_twopass(2*w));
- if !check_ess_logsumexp(w, ess, y) {
+ if !check_ess_log_sum_exp(w, ess, y) {
  exit(1);
  }
 
  /* check underflow */
  w <- [1e-20, log(1e-20)];
  y <- 2e-20;
  ess <- 1.0;
- if !check_ess_logsumexp(w, ess, y) {
+ if !check_ess_log_sum_exp(w, ess, y) {
  exit(1);
  }
 
  /* check empty input */
  x:Real[0];
- if !check_ess_logsumexp(x, 0.0, -inf) {
+ if !check_ess_log_sum_exp(x, 0.0, -inf) {
  exit(1);
  }
 
@@ -58,7 +58,7 @@ program test_basic_logsumexp() {
  w <- cases[n,1..2];
  ess <- cases[n,3];
  y <- cases[n,4];
- if !check_ess_logsumexp(w, ess, y) {
+ if !check_ess_log_sum_exp(w, ess, y) {
  exit(1);
  }
  }
@@ -95,9 +95,9 @@ function log_sum_exp_twopass(w:Real[_]) -> Real {
  *
  * @return Are the results approximately equal to the expected values?
  */
-function check_ess_logsumexp(w:Real[_], ess_expected:Real, y_expected:Real) -> Boolean {
+function check_ess_log_sum_exp(w:Real[_], ess_expected:Real, y_expected:Real) -> Boolean {
  /* roughly half of the significant digits should be correct */
- return check_ess_logsumexp(w, ess_expected, y_expected, 1e-8);
+ return check_ess_log_sum_exp(w, ess_expected, y_expected, 1e-8);
 }
 
 /*
@@ -110,7 +110,7 @@ function check_ess_logsumexp(w:Real[_], ess_expected:Real, y_expected:Real) -> B
  *
  * @return Are the results approximately equal to the expected values?
  */
-function check_ess_logsumexp(w:Real[_], ess_expected:Real, y_expected:Real, reltol:Real) -> Boolean {
+function check_ess_log_sum_exp(w:Real[_], ess_expected:Real, y_expected:Real, reltol:Real) -> Boolean {
  let result <- true;
 
  let y <- log_sum_exp(w);
@@ -139,10 +139,6 @@ function check_ess_logsumexp(w:Real[_], ess_expected:Real, y_expected:Real, relt
  * @return Are the two scalars approximately equal?
  */
 function approx_equal(x1:Real, x2:Real, reltol:Real) -> Boolean {
- // Handle special cases such as `inf`, `-inf` etc. not covered below.
- if x1 == x2 {
- return true;
- }
-
- return abs(x1 - x2) < reltol*max(abs(x1), abs(x2));
+ /* check for equality handles special cases such as `inf`, `-inf` etc. */
+ return x1 == x2 || abs(x1 - x2) < reltol*max(abs(x1), abs(x2));
 }