<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <meta http-equiv="X-UA-Compatible" content="IE=9"/> <title>Square Root</title> <title>CMSIS-DSP: Square Root</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <link href="cmsis.css" rel="stylesheet" type="text/css" /> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript" src="dynsections.js"></script> <script type="text/javascript" src="printComponentTabs.js"></script> <link href="navtree.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="resize.js"></script> <script type="text/javascript" src="navtree.js"></script> <script type="text/javascript"> $(document).ready(initResizable); $(window).load(resizeHeight); </script> <link href="search/search.css" rel="stylesheet" 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search results (closed by default) --> <div id="MSearchResultsWindow"> <iframe src="javascript:void(0)" frameborder="0" name="MSearchResults" id="MSearchResults"> </iframe> </div> <div class="header"> <div class="summary"> <a href="#func-members">Functions</a> </div> <div class="headertitle"> <div class="title">Square Root<div class="ingroups"><a class="el" href="group__groupFastMath.html">Fast Math Functions</a></div></div> </div> </div><!--header--> <div class="contents"> <table class="memberdecls"> <tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a> Functions</h2></td></tr> <tr class="memitem:ga697d82c2747a3302cf44e7c9583da2e8"><td class="memItemLeft" align="right" valign="top">CMSIS_INLINE __STATIC_INLINE <br class="typebreak"/> <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__SQRT.html#ga697d82c2747a3302cf44e7c9583da2e8">arm_sqrt_f32</a> (<a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> in, <a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pOut)</td></tr> <tr class="memdesc:ga697d82c2747a3302cf44e7c9583da2e8"><td class="mdescLeft"> </td><td class="mdescRight">Floating-point square root function. <a href="#ga697d82c2747a3302cf44e7c9583da2e8">More...</a><br/></td></tr> <tr class="separator:ga697d82c2747a3302cf44e7c9583da2e8"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:ga119e25831e141d734d7ef10636670058"><td class="memItemLeft" align="right" valign="top"><a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__SQRT.html#ga119e25831e141d734d7ef10636670058">arm_sqrt_q31</a> (<a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> in, <a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pOut)</td></tr> <tr class="memdesc:ga119e25831e141d734d7ef10636670058"><td class="mdescLeft"> </td><td class="mdescRight">Q31 square root function. <a href="#ga119e25831e141d734d7ef10636670058">More...</a><br/></td></tr> <tr class="separator:ga119e25831e141d734d7ef10636670058"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:ga5abe5ca724f3e15849662b03752c1238"><td class="memItemLeft" align="right" valign="top"><a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__SQRT.html#ga5abe5ca724f3e15849662b03752c1238">arm_sqrt_q15</a> (<a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> in, <a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pOut)</td></tr> <tr class="memdesc:ga5abe5ca724f3e15849662b03752c1238"><td class="mdescLeft"> </td><td class="mdescRight">Q15 square root function. <a href="#ga5abe5ca724f3e15849662b03752c1238">More...</a><br/></td></tr> <tr class="separator:ga5abe5ca724f3e15849662b03752c1238"><td class="memSeparator" colspan="2"> </td></tr> </table> <a name="details" id="details"></a><h2 class="groupheader">Description</h2> <p>Computes the square root of a number. There are separate functions for Q15, Q31, and floating-point data types. The square root function is computed using the Newton-Raphson algorithm. This is an iterative algorithm of the form: </p> <pre> x1 = x0 - f(x0)/f'(x0) </pre><p> where <code>x1</code> is the current estimate, <code>x0</code> is the previous estimate, and <code>f'(x0)</code> is the derivative of <code>f()</code> evaluated at <code>x0</code>. For the square root function, the algorithm reduces to: </p> <pre> x0 = in/2 [initial guess] x1 = 1/2 * ( x0 + in / x0) [each iteration] </pre> <h2 class="groupheader">Function Documentation</h2> <a class="anchor" id="ga697d82c2747a3302cf44e7c9583da2e8"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">CMSIS_INLINE __STATIC_INLINE <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> arm_sqrt_f32 </td> <td>(</td> <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> </td> <td class="paramname"><em>in</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> * </td> <td class="paramname"><em>pOut</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. </td></tr> <tr><td class="paramdir">[out]</td><td class="paramname">pOut</td><td>square root of input value. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if input value is positive value or ARM_MATH_ARGUMENT_ERROR if <code>in</code> is negative value and returns zero output for negative values. </dd></dl> <p>References <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a74897e18d4b8f62b12a7d8a01dd2bb35">ARM_MATH_ARGUMENT_ERROR</a>, and <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a9f8b2a10bd827fb4600e77d455902eb0">ARM_MATH_SUCCESS</a>.</p> <p>Referenced by <a class="el" href="group__cmplx__mag.html#gae45024c497392cde2ae358a76d435213">arm_cmplx_mag_f32()</a>, <a class="el" href="group__RMS.html#ga0e3ab1b57da32d45388d1fa90d7fd88c">arm_rms_f32()</a>, and <a class="el" href="group__STD.html#ga4969b5b5f3d001377bc401a3ee99dfc2">arm_std_f32()</a>.</p> </div> </div> <a class="anchor" id="ga5abe5ca724f3e15849662b03752c1238"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> arm_sqrt_q15 </td> <td>(</td> <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> </td> <td class="paramname"><em>in</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> * </td> <td class="paramname"><em>pOut</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. The range of the input value is [0 +1) or 0x0000 to 0x7FFF. </td></tr> <tr><td class="paramdir">[out]</td><td class="paramname">pOut</td><td>square root of input value. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if input value is positive value or ARM_MATH_ARGUMENT_ERROR if <code>in</code> is negative value and returns zero output for negative values.</dd></dl> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. The range of the input value is [0 +1) or 0x0000 to 0x7FFF. </td></tr> <tr><td class="paramdir">[out]</td><td class="paramname">*pOut</td><td>square root of input value. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if the input value is positive and ARM_MATH_ARGUMENT_ERROR if the input is negative. For negative inputs, the function returns *pOut = 0. </dd></dl> <p>References <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a74897e18d4b8f62b12a7d8a01dd2bb35">ARM_MATH_ARGUMENT_ERROR</a>, and <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a9f8b2a10bd827fb4600e77d455902eb0">ARM_MATH_SUCCESS</a>.</p> <p>Referenced by <a class="el" href="group__cmplx__mag.html#ga0a4a8f77a6a51d9b3f3b9d729f85b7a4">arm_cmplx_mag_q15()</a>, <a class="el" href="group__RMS.html#gaf5b836b72dda9e5dfbbd17c7906fd13f">arm_rms_q15()</a>, and <a class="el" href="group__STD.html#gaf9d27afa9928ff28a63cd98ea9218a72">arm_std_q15()</a>.</p> </div> </div> <a class="anchor" id="ga119e25831e141d734d7ef10636670058"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> arm_sqrt_q31 </td> <td>(</td> <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> </td> <td class="paramname"><em>in</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> * </td> <td class="paramname"><em>pOut</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. The range of the input value is [0 +1) or 0x00000000 to 0x7FFFFFFF. </td></tr> <tr><td class="paramdir">[out]</td><td class="paramname">pOut</td><td>square root of input value. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if input value is positive value or ARM_MATH_ARGUMENT_ERROR if <code>in</code> is negative value and returns zero output for negative values.</dd></dl> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. The range of the input value is [0 +1) or 0x00000000 to 0x7FFFFFFF. </td></tr> <tr><td class="paramdir">[out]</td><td class="paramname">*pOut</td><td>square root of input value. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if the input value is positive and ARM_MATH_ARGUMENT_ERROR if the input is negative. For negative inputs, the function returns *pOut = 0. </dd></dl> <p>References <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a74897e18d4b8f62b12a7d8a01dd2bb35">ARM_MATH_ARGUMENT_ERROR</a>, and <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a9f8b2a10bd827fb4600e77d455902eb0">ARM_MATH_SUCCESS</a>.</p> <p>Referenced by <a class="el" href="group__cmplx__mag.html#ga14f82f9230e9d96d5b9774e2fefcb7be">arm_cmplx_mag_q31()</a>, <a class="el" href="group__RMS.html#gae33015fda23fc44e7ead5e5ed7e8d314">arm_rms_q31()</a>, and <a class="el" href="group__STD.html#ga39495e74f96116178be085c9dc7742f5">arm_std_q31()</a>.</p> </div> </div> </div><!-- contents --> </div><!-- doc-content --> <!-- start footer part --> <div id="nav-path" class="navpath"><!-- id is needed for treeview function! --> <ul> <li class="footer">Generated on Wed Feb 8 2017 10:20:51 for CMSIS-DSP by ARM Ltd. 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