diff options
| author | Andrey Hristov <andrey@php.net> | 2005-05-02 12:12:04 +0000 |
|---|---|---|
| committer | Andrey Hristov <andrey@php.net> | 2005-05-02 12:12:04 +0000 |
| commit | 7a4eb25870e48661e1b356b71cac3297550a1758 (patch) | |
| tree | 84b53f3f850abf7715106cb33356ff0d23ea9918 /ext/standard/math.c | |
| parent | 6141c5690d251480852e185ed00f231e433cfef4 (diff) | |
| download | php-git-7a4eb25870e48661e1b356b71cac3297550a1758.tar.gz | |
add also math_variance() which uses the same calculation as math_std_dev()
Diffstat (limited to 'ext/standard/math.c')
| -rw-r--r-- | ext/standard/math.c | 49 |
1 files changed, 36 insertions, 13 deletions
diff --git a/ext/standard/math.c b/ext/standard/math.c index 528b864cdd..3e27103e3c 100644 --- a/ext/standard/math.c +++ b/ext/standard/math.c @@ -1183,22 +1183,12 @@ PHP_FUNCTION(fmod) /* }}} */ - -/* {{{ proto float math_std_dev(array a) - Returns the standard deviation */ -PHP_FUNCTION(math_std_dev) +static long double php_population_variance(zval *arr) { double mean, sum = 0.0, vr = 0.0; - zval *arr, **entry; + zval **entry; HashPosition pos; - if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &arr) == 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; - } 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); @@ -1215,8 +1205,41 @@ PHP_FUNCTION(math_std_dev) vr += d*d; zend_hash_move_forward_ex(Z_ARRVAL_P(arr), &pos); } + return (vr / zend_hash_num_elements(Z_ARRVAL_P(arr))); +} + +/* {{{ proto float math_variance(array a) + Returns the standard deviation */ +PHP_FUNCTION(math_variance) +{ + zval *arr; + + if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &arr) == 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(sqrt(vr / zend_hash_num_elements(Z_ARRVAL_P(arr)))); +/* {{{ proto float math_std_dev(array a) + Returns the standard deviation */ +PHP_FUNCTION(math_std_dev) +{ + zval *arr; + + if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &arr) == 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))); } /* }}} */ |