[英]sum of double variables
I have problem tyring to do some basic addition. 我在尝试进行一些基本加法时遇到问题。 I don't understand why the returned value for J11 is 0 while A11*G11 and A12*G21 have finite values. 我不明白为什么J11的返回值为0而A11 * G11和A12 * G21具有有限值。 I know it has to do with variable types - most likely. 我知道这与变量类型有关-很可能。 Your help is much appreciated. 非常感谢您的帮助。 Here is the code: 这是代码:
#include <vector>
#include <iostream>
#include <fstream>
#include <cmath>
#include <cstdlib>
#include <set>
using namespace std;
void simple()
{
double G11,G12,G13,G21,G22,G23,G31,G32;
double G33,G41,G42,G43,G51,G52,G53,G61;
double G62,G63,G71,G72,G73,G81,G82,G83;
double J11;
double xx,yy,zz;
double A11,A12;
vector<double> xcoor;
vector<double> ycoor;
vector<double> zcoor;
double G1=1/sqrt(3);
double G2=-1/sqrt(3);
xcoor.push_back(G1);
xcoor.push_back(G2);
xcoor.push_back(G1);
xcoor.push_back(G2);
xcoor.push_back(G1);
xcoor.push_back(G2);
xcoor.push_back(G1);
xcoor.push_back(G2);
ycoor.push_back(G1);
ycoor.push_back(G2);
ycoor.push_back(G2);
ycoor.push_back(G1);
ycoor.push_back(G1);
ycoor.push_back(G2);
ycoor.push_back(G2);
ycoor.push_back(G1);
zcoor.push_back(G2);
zcoor.push_back(G2);
zcoor.push_back(G2);
zcoor.push_back(G2);
zcoor.push_back(G1);
zcoor.push_back(G1);
zcoor.push_back(G1);
zcoor.push_back(G1);
for (size_t z = 0 ; z < 43 ; z++) {
for (size_t y = 0 ; y < 43 ; y++) {
for (size_t x = 0 ; x < 43 ; x++) {
G11=x;
G12=y;
G13=z;
G21=x;
G22=y+1.;
G23=z;
G31=x+1.;
G32=y+1.;
G33=z;
G41=x+1.;
G42=y;
G43=z;
G51=x;
G52=y;
G53=z+1.;
G61=x;
G62=y+1.;
G63=z+1.;
G71=x+1.;
G72=y+1.;
G73=z+1.;
G81=x+1.;
G82=y;
G83=z+1.;
for(size_t t = 0 ; t < 8 ; t++){
xx = xcoor[t];
yy = ycoor[t];
zz = zcoor[t];
A11=(-1./8.)*(1-yy)*(1-zz);
A12=(1./8.)*(1-yy)*(1-zz);
J11 = A11 * G11 + A12 * G21;
cout<<J11<<endl;
}
}
}
}
}
int main ()
{
simple();
cout << "Computation done." << endl;
return 0;
}
This has to be zero: 必须为零:
J11 = A11 * G11 + A12 * G21;
because A11 = -A12 as you can see here: 因为您可以在此处看到A11 = -A12:
A11=(-1./8.)*(1-yy)*(1-zz);
A12=(1./8.)*(1-yy)*(1-zz);
and G11 = G21 because of: 并且G11 = G21是因为:
G11 = x
G21 = x
Nevertheless I have no idea what you are trying to accomplish with this code. 但是,我不知道您要用此代码完成什么。
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