Why not catching division by zero?
Stefan
Andrey Hristov wrote:
andrey Mon May 2 05:17:50 2005 EDT
Added files: /php-src/ext/standard/tests/math math_std_dev.phpt
Modified files: /php-src/ext/standard basic_functions.c math.c php_math.h Log:
add math_std_dev()
http://cvs.php.net/diff.php/php-src/ext/standard/basic_functions.c?r1=1.711&r2=1.712&ty=u
Index: php-src/ext/standard/basic_functions.c
diff -u php-src/ext/standard/basic_functions.c:1.711 php-src/ext/standard/basic_functions.c:1.712
--- php-src/ext/standard/basic_functions.c:1.711 Wed Apr 27 11:45:36 2005
+++ php-src/ext/standard/basic_functions.c Mon May 2 05:17:49 2005
@@ -17,7 +17,7 @@
+----------------------------------------------------------------------+
*/
-/* $Id: basic_functions.c,v 1.711 2005/04/27 15:45:36 dmitry Exp $ */
+/* $Id: basic_functions.c,v 1.712 2005/05/02 09:17:49 andrey Exp $ */
#include "php.h"
#include "php_streams.h"
@@ -415,6 +415,7 @@
PHP_FE(base_convert, NULL)
PHP_FE(number_format, NULL)
PHP_FE(fmod, NULL)
+ PHP_FE(math_std_dev, NULL)
#ifdef HAVE_INET_NTOP
PHP_NAMED_FE(inet_ntop, php_inet_ntop, NULL)
#endif
http://cvs.php.net/diff.php/php-src/ext/standard/math.c?r1=1.119&r2=1.120&ty=u
Index: php-src/ext/standard/math.c
diff -u php-src/ext/standard/math.c:1.119 php-src/ext/standard/math.c:1.120
--- php-src/ext/standard/math.c:1.119 Mon Dec 13 19:37:19 2004
+++ php-src/ext/standard/math.c Mon May 2 05:17:49 2005
@@ -19,7 +19,7 @@
+----------------------------------------------------------------------+
*/
-/* $Id: math.c,v 1.119 2004/12/14 00:37:19 iliaa Exp $ */
+/* $Id: math.c,v 1.120 2005/05/02 09:17:49 andrey Exp $ */
#include "php.h"
#include "php_math.h"
@@ -1182,6 +1182,40 @@
}
/* }}} */
+
+
+/* {{{ proto float math_std_dev(array a)
+ Returns the standard deviation */
+PHP_FUNCTION(math_std_dev)
+{
+ double mean, sum = 0.0, vr = 0.0;
+ zval *arr, **entry;
+ HashPosition pos;
+
+ if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &arr) == FAILURE) {
+ return;
+ }
+ 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) {
+ convert_to_double_ex(entry);
+ 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));
+
+ 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) {
+ double d;
+ convert_to_double_ex(entry);
+ d = Z_DVAL_PP(entry) - mean;
+ vr += d*d;
+ zend_hash_move_forward_ex(Z_ARRVAL_P(arr), &pos);
+ }
+
+ RETURN_DOUBLE(sqrt(vr / zend_hash_num_elements(Z_ARRVAL_P(arr))));
+}
+/* }}} */
+
/*
* Local variables:
* tab-width: 4
http://cvs.php.net/diff.php/php-src/ext/standard/php_math.h?r1=1.23&r2=1.24&ty=u
Index: php-src/ext/standard/php_math.h
diff -u php-src/ext/standard/php_math.h:1.23 php-src/ext/standard/php_math.h:1.24
--- php-src/ext/standard/php_math.h:1.23 Tue Sep 21 14:09:29 2004
+++ php-src/ext/standard/php_math.h Mon May 2 05:17:49 2005
@@ -17,7 +17,7 @@
+----------------------------------------------------------------------+
*/
-/* $Id: php_math.h,v 1.23 2004/09/21 18:09:29 fmk Exp $ */
+/* $Id: php_math.h,v 1.24 2005/05/02 09:17:49 andrey Exp $ */
#ifndef PHP_MATH_H
#define PHP_MATH_H
@@ -59,6 +59,7 @@
PHP_FUNCTION(base_convert);
PHP_FUNCTION(number_format);
PHP_FUNCTION(fmod);
+PHP_FUNCTION(math_std_dev);
PHP_FUNCTION(deg2rad);
PHP_FUNCTION(rad2deg);
http://cvs.php.net/co.php/php-src/ext/standard/tests/math/math_std_dev.phpt?r=1.1&p=1 Index: php-src/ext/standard/tests/math/math_std_dev.phpt +++ php-src/ext/standard/tests/math/math_std_dev.phpt --TEST-- math_std_dev() tests --FILE-- <?php $a=array(4, 1, 7); $dev=math_std_dev($a); var_dump(sprintf("%2.9f", $dev)); ?> --EXPECT-- string(11) "2.449489743"
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