You forgot to update the protos to add the second parameter. Nuno
----- Original Message ----- From: "Andrey Hristov" <[EMAIL PROTECTED]>
To: <php-cvs@lists.php.net>
Sent: Monday, May 02, 2005 1:29 PM
Subject: [PHP-CVS] cvs: php-src /ext/standard math.c /ext/standard/tests/math math_std_dev.phpt
andrey Mon May 2 08:29:38 2005 EDT
Modified files: /php-src/ext/standard math.c /php-src/ext/standard/tests/math math_std_dev.phpt Log: add possibility to calculate the standard deviation and the variance on a sample - the formulae are slightly different.
http://cvs.php.net/diff.php/php-src/ext/standard/math.c?r1=1.122&r2=1.123&ty=u
Index: php-src/ext/standard/math.c
diff -u php-src/ext/standard/math.c:1.122 php-src/ext/standard/math.c:1.123
--- php-src/ext/standard/math.c:1.122 Mon May 2 08:12:04 2005
+++ php-src/ext/standard/math.c Mon May 2 08:29:37 2005
@@ -19,7 +19,7 @@
+----------------------------------------------------------------------+ */
-/* $Id: math.c,v 1.122 2005/05/02 12:12:04 andrey Exp $ */ +/* $Id: math.c,v 1.123 2005/05/02 12:29:37 andrey Exp $ */
#include "php.h" #include "php_math.h" @@ -1183,11 +1183,14 @@ /* }}} */
-static long double php_population_variance(zval *arr) +static long double php_population_variance(zval *arr, zend_bool sample) { double mean, sum = 0.0, vr = 0.0; zval **entry; HashPosition pos; + int elements_num; + + elements_num = zend_hash_num_elements(Z_ARRVAL_P(arr));
zend_hash_internal_pointer_reset_ex(Z_ARRVAL_P(arr), &pos);
while (zend_hash_get_current_data_ex(Z_ARRVAL_P(arr), (void **)&entry, &pos) == SUCCESS) {
@@ -1195,7 +1198,7 @@
sum += Z_DVAL_PP(entry);
zend_hash_move_forward_ex(Z_ARRVAL_P(arr), &pos);
}
- mean = sum / zend_hash_num_elements(Z_ARRVAL_P(arr));
+ mean = sum / elements_num;
zend_hash_internal_pointer_reset_ex(Z_ARRVAL_P(arr), &pos);
while (zend_hash_get_current_data_ex(Z_ARRVAL_P(arr), (void **)&entry, &pos) == SUCCESS) {
@@ -1205,7 +1208,10 @@
vr += d*d;
zend_hash_move_forward_ex(Z_ARRVAL_P(arr), &pos);
}
- return (vr / zend_hash_num_elements(Z_ARRVAL_P(arr)));
+ if (sample) {
+ --elements_num;
+ }
+ return (vr / elements_num);
}
/* {{{ proto float math_variance(array a) @@ -1213,15 +1219,16 @@ PHP_FUNCTION(math_variance) { zval *arr; + zend_bool sample = 0;
- if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &arr) == FAILURE) {
+ if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a|b", &arr, &sample) == FAILURE) {
return;
}
if (zend_hash_num_elements(Z_ARRVAL_P(arr)) == 0) {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "The array has zero elements");
RETURN_FALSE;
}
- RETURN_DOUBLE(php_population_variance(arr));
+ RETURN_DOUBLE(php_population_variance(arr, sample));
}
/* }}} */
@@ -1231,15 +1238,16 @@ PHP_FUNCTION(math_std_dev) { zval *arr; + zend_bool sample = 0;
- if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &arr) == FAILURE) {
+ if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a|b", &arr, &sample) == FAILURE) {
return;
}
if (zend_hash_num_elements(Z_ARRVAL_P(arr)) == 0) {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "The array has zero elements");
RETURN_FALSE;
}
- RETURN_DOUBLE(sqrt(php_population_variance(arr)));
+ RETURN_DOUBLE(sqrt(php_population_variance(arr, sample)));
}
/* }}} */
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