#include< math.h> [英] #include <math.h>
问题描述
我似乎遇到了一些数学函数（pow，sqrt，
acos）。他们是我在我的代码中使用的唯一一个，他们阻止程序
编译。我得到一个未定义的引用''pow''错误。这是我的代码的
相关部分。
我们将非常感谢您的帮助。谢谢！
*遗传算法模块
*
* /
＃包括< stdio.h>
#include< stdlib.h>
#include< time.h>
#include< ; math.h>
#include" string.h"
/ * GetSD
*
*此函数返回dataT *数组中特征向量的标准差
*。
* /
静态双GetSD（dataT * dataArr []，int data_size，int features []，double
mean []）{
int i，j;
double data_vect [GENES_PER_CHROM ]，data_sum，mean_sum，ang_sum，dotprod，
data_norm，mean_norm，angle;
double sd;
ang_sum = 0 ;
for（i = 0; i< data_size; i ++）{
for（j = 0; j< GENES_PER_CHROM; j ++）{
data_vect [j] = dataArr [i] - > val [（features [j]）];
}
//得到两个向量的点积
dotprod = 0; ; j< GENES_PER_CHROM; j ++）{
dotprod + = data_vect [j] *表示[j];
}
//获得规范
data_sum = 0;
mean_sum = 0;
for（j = 0; j< GENES_PER_CHROM; j ++）{
data_sum + = pow（data_vect [j]，2）;
mean_sum + = pow（mean [j]，2）;
}
data_norm = sqrt（data_sum）;
mean_norm = sqrt（mean_sum）;
//计算角度
angle = acos（dotprod /（data_norm * mean_norm））;
ang_sum + = pow（angle，2）;
}
sd = sqrt（ang_sum /（data_size - 1））;
返回sd;
}
Hi,
I seem to be having trouble with some of my math functions (pow, sqrt,
acos). They''re the only ones I use in my code and they prevent the program
from compiling. I get a "undefined reference to ''pow''" error. Here is the
relevant portion of my code.
Your help would be appreciated. Thanks!
* Genetic Algorithm module
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
#include "string.h"
/* GetSD
*
* This function returns the standard deviation of the feature vectors
* in a dataT * array.
*/
static double GetSD(dataT *dataArr[], int data_size, int features[], double
mean[]) {
int i, j;
double data_vect[GENES_PER_CHROM], data_sum, mean_sum, ang_sum, dotprod,
data_norm, mean_norm, angle;
double sd;
ang_sum = 0;
for(i = 0; i < data_size; i++) {
for(j = 0; j < GENES_PER_CHROM; j++) {
data_vect[j] = dataArr[i]->val[(features[j])];
}
// get dot product of the two vectors
dotprod = 0;
for(j = 0; j < GENES_PER_CHROM; j++) {
dotprod += data_vect[j] * mean[j];
}
// get the norms
data_sum = 0;
mean_sum = 0;
for(j = 0; j < GENES_PER_CHROM; j++) {
data_sum += pow(data_vect[j], 2);
mean_sum += pow(mean[j], 2);
}
data_norm = sqrt(data_sum);
mean_norm = sqrt(mean_sum);
// compute the angle
angle = acos(dotprod/(data_norm * mean_norm));
ang_sum += pow(angle, 2);
}
sd = sqrt(ang_sum / (data_size - 1));
return sd;
}
推荐答案
Darius Fatakia< da ************ @ yahoo.com>写道：
Darius Fatakia <da************@yahoo.com> wrote:
我似乎遇到了一些数学函数（pow，sqrt，
acos）。它们是我在我的代码中使用的唯一的，它们阻止程序编译。我得到一个未定义的引用''pow''错误。这是我的代码的相关部分。
Hi, I seem to be having trouble with some of my math functions (pow, sqrt,
acos). They''re the only ones I use in my code and they prevent the program
from compiling. I get a "undefined reference to ''pow''" error. Here is the
relevant portion of my code.
您很可能遇到链接问题。阅读你的系统
文档，了解如何在数学库中链接。
< OT>将-lm附加到编译行可能会有效。 < / OT>
Alex
You are most likely having a linking problem. Read your system
documentation to find out how to link in the math library.
<OT> Appending -lm to your compile line might work. </OT>
Alex
Darius Fatakia写道：
Darius Fatakia wrote:
I似乎在我的一些数学函数（pow，sqrt，
acos）上遇到了麻烦。它们是我在我的代码中使用的唯一的，它们阻止程序编译。我得到一个未定义的引用''pow''错误。这是我的代码的相关部分。
cat gam.c
typedef struct dataT {
double * val;
} dataT;
#define GENES_PER_CHROM 1024
/ *
*遗传算法模块
* /
#include< stdio.h>
#include< stdlib.h>
#include< time.h>
#include< math.h>
#include" string.h"
/ * GetSD
*
*此函数返回dataT *数组中特征向量的标准差
*。
* /
static
double GetSD（dataT * dataArr []，
int data_size，int features []，double mean []）{
double data_vect [GENES_PER_CHROM];
double ang_sum = 0.0;
for（int i = 0; i< data_size; ++ i）{
for（int j = 0; j< GENES_PER_CHROM; ++ j）{
data_vect [j] = dataArr [i] - > val [（features [j]） ];
}
//得到两者的点积向量
double dotprod = 0.0;
for（int j = 0; j< GENES_PER_CHROM; ++ j）{
dotprod + = data_vect [j] *表示[j];
}
//得到规范
double data_sum = 0.0;
double mean_sum = 0.0;
for（int j = 0; j< GENES_PER_CHROM; ++ j）{
data_sum + = pow（data_vect [j]，2）;
mean_sum + = pow（mean [j]，2）;
}
double data_norm = sqrt（data_sum）;
double mean_norm = sqrt（mean_sum）;
//计算角度
double angle = acos（dotprod /（data_norm * mean_norm））;
ang_sum + = pow（angle，2）;
}
返回sqrt（ang_sum /（data_size - 1））;
}
int main（int argc，char * argv []）{
dataT * dataArr [GENES_PER_CHROM];
int data_size = 1024;
int features [1024];
双重均值[GENES_PER_CHROM];
GetSD（dataArr，data_size，features，mean）;
返回0;
}
gcc -Wall -std = c99 -pedantic -o gam gam.c -lm
I seem to be having trouble with some of my math functions (pow, sqrt,
acos). They''re the only ones I use in my code and they prevent the program
from compiling. I get a "undefined reference to ''pow''" error. Here is the
relevant portion of my code. cat gam.c typedef struct dataT {
double* val;
} dataT;
#define GENES_PER_CHROM 1024
/*
* Genetic Algorithm module
*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
#include "string.h"
/* GetSD
*
* This function returns the standard deviation
* of the feature vectors in a dataT* array.
*/
static
double GetSD(dataT* dataArr[],
int data_size, int features[], double mean[]) {
double data_vect[GENES_PER_CHROM];
double ang_sum = 0.0;
for(int i = 0; i < data_size; ++i) {
for(int j = 0; j < GENES_PER_CHROM; ++j) {
data_vect[j] = dataArr[i]->val[(features[j])];
}
// get dot product of the two vectors
double dotprod = 0.0;
for(int j = 0; j < GENES_PER_CHROM; ++j) {
dotprod += data_vect[j]*mean[j];
}
// get the norms
double data_sum = 0.0;
double mean_sum = 0.0;
for(int j = 0; j < GENES_PER_CHROM; ++j) {
data_sum += pow(data_vect[j], 2);
mean_sum += pow(mean[j], 2);
}
double data_norm = sqrt(data_sum);
double mean_norm = sqrt(mean_sum);
// compute the angle
double angle = acos(dotprod/(data_norm*mean_norm));
ang_sum += pow(angle, 2);
}
return sqrt(ang_sum/(data_size - 1));
}
int main(int argc, char* argv[]) {
dataT* dataArr[GENES_PER_CHROM];
int data_size = 1024;
int features[1024];
double mean[GENES_PER_CHROM];
GetSD(dataArr, data_size, features, mean);
return 0;
}
gcc -Wall -std=c99 -pedantic -o gam gam.c -lm
如果包含math.h，则需要在libm.a中使用-lm选项进行链接。
If you include math.h, you need to link in libm.a with the -lm option.
On星期一，2003年11月24日16:52:07 -0800，Darius Fatakia写道：
On Mon, 24 Nov 2003 16:52:07 -0800, Darius Fatakia wrote:
我似乎遇到了一些问题功能（pow，sqrt，
acos）。它们是我在我的代码中使用的唯一的，它们阻止程序编译。我得到一个未定义的引用''pow''错误。这是我的代码的相关部分。
Hi,
I seem to be having trouble with some of my math functions (pow, sqrt,
acos). They''re the only ones I use in my code and they prevent the program
from compiling. I get a "undefined reference to ''pow''" error. Here is the
relevant portion of my code.
听起来像链接器错误 - 您是否链接数学库？某些特别受欢迎的编译器，特别是在Linux世界中广泛使用的，有一些特殊的编译器，
，它具有不包括数学的最终脑死亡习惯
默认情况下
库。假设你正在使用这个编译器，试试这样的东西
：
gcc -lm file.c
Sounds like a linker error - are you linking the math libraries? There''s
a certain, popular compiler, especially widely used in the Linux world,
which has the terminally brain-dead habit of not including the math
libraries by default. Assuming you''re using this compiler, try something
like this:
gcc -lm file.c
这篇关于#include< math.h>的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
