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author | Mihai Moldovan <ionic@ionic.de> | 2017-08-25 12:44:49 +0200 |
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committer | Mihai Moldovan <ionic@ionic.de> | 2017-08-25 12:44:49 +0200 |
commit | ae0a2bfdeb9ceacb80aa03375353039d425b14b9 (patch) | |
tree | daec55145477bcec69273e03d5c9ff10c10a4137 /nx-X11/lib/src/xcms/cmsMath.c | |
parent | cbe2c0e44f412d07024207f374c0f56684adb088 (diff) | |
parent | 3b7e5a42f5abecb903a9d730d163d704520efb07 (diff) | |
download | nx-libs-ae0a2bfdeb9ceacb80aa03375353039d425b14b9.tar.gz nx-libs-ae0a2bfdeb9ceacb80aa03375353039d425b14b9.tar.bz2 nx-libs-ae0a2bfdeb9ceacb80aa03375353039d425b14b9.zip |
Merge branch 'sunweaver-pr/libnx-x11-autoreconf' into 3.6.x
Attributes GH PR #498: https://github.com/ArcticaProject/nx-libs/pull/498
Diffstat (limited to 'nx-X11/lib/src/xcms/cmsMath.c')
-rw-r--r-- | nx-X11/lib/src/xcms/cmsMath.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/nx-X11/lib/src/xcms/cmsMath.c b/nx-X11/lib/src/xcms/cmsMath.c new file mode 100644 index 000000000..487eb3f9c --- /dev/null +++ b/nx-X11/lib/src/xcms/cmsMath.c @@ -0,0 +1,140 @@ + +/* + +Copyright 1990, 1998 The Open Group + +Permission to use, copy, modify, distribute, and sell this software and its +documentation for any purpose is hereby granted without fee, provided that +the above copyright notice appear in all copies and that both that +copyright notice and this permission notice appear in supporting +documentation. + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN +AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +Except as contained in this notice, the name of The Open Group shall not be +used in advertising or otherwise to promote the sale, use or other dealings +in this Software without prior written authorization from The Open Group. + +*/ + +/* + * Stephen Gildea, MIT X Consortium, January 1991 + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif +#include "Xlibint.h" +#include "Xcmsint.h" + +#ifdef DEBUG +#include <stdio.h> +#endif + +#include <float.h> +#ifndef DBL_EPSILON +#define DBL_EPSILON 1e-6 +#endif + +#ifdef _X_ROOT_STATS +int cbrt_loopcount; +int sqrt_loopcount; +#endif + +/* Newton's Method: x_n+1 = x_n - ( f(x_n) / f'(x_n) ) */ + + +/* for cube roots, x^3 - a = 0, x_new = x - 1/3 (x - a/x^2) */ + +double +_XcmsCubeRoot(double a) +{ + register double abs_a, cur_guess, delta; + +#ifdef DEBUG + printf("_XcmsCubeRoot passed in %g\n", a); +#endif +#ifdef _X_ROOT_STATS + cbrt_loopcount = 0; +#endif + if (a == 0.) + return 0.; + + abs_a = a<0. ? -a : a; /* convert to positive to speed loop tests */ + + /* arbitrary first guess */ + if (abs_a > 1.) + cur_guess = abs_a/8.; + else + cur_guess = abs_a*8.; + + do { +#ifdef _X_ROOT_STATS + cbrt_loopcount++; +#endif + delta = (cur_guess - abs_a/(cur_guess*cur_guess))/3.; + cur_guess -= delta; + if (delta < 0.) delta = -delta; + } while (delta >= cur_guess*DBL_EPSILON); + + if (a < 0.) + cur_guess = -cur_guess; + +#ifdef DEBUG + printf("_XcmsCubeRoot returning %g\n", cur_guess); +#endif + return cur_guess; +} + + + +/* for square roots, x^2 - a = 0, x_new = x - 1/2 (x - a/x) */ + +double +_XcmsSquareRoot(double a) +{ + register double cur_guess, delta; + +#ifdef DEBUG + printf("_XcmsSquareRoot passed in %g\n", a); +#endif +#ifdef _X_ROOT_STATS + sqrt_loopcount = 0; +#endif + if (a == 0.) + return 0.; + + if (a < 0.) { + /* errno = EDOM; */ + return 0.; + } + + /* arbitrary first guess */ + if (a > 1.) + cur_guess = a/4.; + else + cur_guess = a*4.; + + do { +#ifdef _X_ROOT_STATS + sqrt_loopcount++; +#endif + delta = (cur_guess - a/cur_guess)/2.; + cur_guess -= delta; + if (delta < 0.) delta = -delta; + } while (delta >= cur_guess*DBL_EPSILON); + +#ifdef DEBUG + printf("_XcmsSquareRoot returning %g\n", cur_guess); +#endif + return cur_guess; +} + |