0c9bf8ae
 dmayerich
Case-sensitive er...
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
__device__ double g(double v0, double v1)
{
return (v0 + v1)*log(abs(v0+v1)) + (v0-v1)*log(abs(v0-v1));
}
__device__ double hfin(double v0, double v1, double dv)
{
double e = 0.001;
double t0 = g(v0+e, v1-dv)/dv;
double t1 = 2*g(v0+e, v1)/dv;
double t2 = g(v0+e, v1+dv)/dv;
return -1.0/PI * (t0 - t1 + t2);
}
__global__ void devKramersKronig(double* gpuN, double* gpuK, int numVals, double nuStart, double nuEnd, double nOffset)
{
int i = blockIdx.x * blockDim.x + threadIdx.x;
if(i >= numVals) return;
double nuDelta = (nuEnd - nuStart)/(numVals - 1);
double nu = nuStart + i*nuDelta;
double n = 0.0;
double jNu;
double jK;
for(int j=1; j<numVals-1; j++)
{
jNu = nuStart + j*nuDelta;
jK = gpuK[j];
n += hfin(nu, jNu, nuDelta) * jK;
}
gpuN[i] = n + nOffset;
}
void cudaKramersKronig(double* cpuN, double* cpuK, int nVals, double nuStart, double nuEnd, double nOffset)
{
double* gpuK;
HANDLE_ERROR(cudaMalloc(&gpuK, sizeof(double)*nVals));
HANDLE_ERROR(cudaMemcpy(gpuK, cpuK, sizeof(double)*nVals, cudaMemcpyHostToDevice));
double* gpuN;
HANDLE_ERROR(cudaMalloc(&gpuN, sizeof(double)*nVals));
dim3 block(BLOCK_SIZE*BLOCK_SIZE);
dim3 grid(nVals/block.x + 1);
devKramersKronig<<<grid, block>>>(gpuN, gpuK, nVals, nuStart, nuEnd, nOffset);
HANDLE_ERROR(cudaMemcpy(cpuN, gpuN, sizeof(double)*nVals, cudaMemcpyDeviceToHost));
//free resources
HANDLE_ERROR(cudaFree(gpuK));
HANDLE_ERROR(cudaFree(gpuN));
}
__global__ void devComputeSpectrum(double* I, double2* B, double* alpha, int Nl,
int nSamples, double oThetaI, double oThetaO, double cThetaI, double cThetaO)
{
int i = blockIdx.x * blockDim.x + threadIdx.x;
//compute the delta-theta value
double dTheta = (oThetaO - oThetaI)/nSamples;
//allocate space for the Legendre polynomials
double Ptheta[2];
double cosTheta, theta;
cuDoubleComplex Us;
cuDoubleComplex UsSample;
cuDoubleComplex U;
//cuComplex Ui;
//Ui.x = 2*PI;
//Ui.y = 0.0;
cuDoubleComplex numer;
numer.x = 0.0;
cuDoubleComplex exp_numer;
cuDoubleComplex iL;
cuDoubleComplex imag;
imag.x = 0.0; imag.y = 1.0;
double realFac;
cuDoubleComplex complexFac;
double PlTheta;
double Isum = 0.0;
//float maxVal = 0;
//float val;
for(int iTheta = 0; iTheta < nSamples; iTheta++)
{
//calculate theta
theta = iTheta * dTheta + oThetaI;
cosTheta = cos(theta);
//initialize the theta Legendre polynomial
Ptheta[0] = 1.0;
Ptheta[1] = cosTheta;
//initialize the scattered field
Us.x = Us.y = 0.0;
iL.x = 1.0;
iL.y = 0.0;
for(int l = 0; l<Nl; l++)
{
//compute the theta legendre polynomial
if(l == 0)
PlTheta = Ptheta[0];
else if(l == 1)
PlTheta = Ptheta[1];
else
{
PlTheta = ((2*l - 1)*cosTheta*Ptheta[1] - (l - 1)*Ptheta[0])/l;
Ptheta[0] = Ptheta[1];
Ptheta[1] = PlTheta;
}
//compute the real components of the scattered field
realFac = alpha[l] * PlTheta;
//compute the complex components of the scattered field
numer.x = 0.0;
numer.y = -(l*PI)/2.0;
exp_numer = cExp(numer);
complexFac = cMult(B[Nl * i + l], exp_numer);
complexFac = cMult(complexFac, iL);
//combine the real and complex components
UsSample = cMult(complexFac, realFac);
Us = cAdd(Us, UsSample);
//increment the imaginary exponent i^l
iL = cMult(iL, imag);
}
//sum the scattered and incident fields
if(theta >= cThetaI && theta <= cThetaO)
U = cAdd(Us, 2*PI);
else
U = Us;
Isum += (U.x*U.x + U.y*U.y) * sin(theta) * 2 * PI * dTheta;
}
I[i] = Isum;
}
void cudaComputeSpectrum(double* cpuI, double* cpuB, double* cpuAlpha,
int Nl, int nLambda, double oThetaI, double oThetaO, double cThetaI, double cThetaO, int nSamples)
{
//copy everything to the GPU
double2* gpuB;
HANDLE_ERROR(cudaMalloc(&gpuB, sizeof(double2) * nLambda * Nl));
HANDLE_ERROR(cudaMemcpy(gpuB, cpuB, sizeof(double2) * nLambda * Nl, cudaMemcpyHostToDevice));
double* gpuAlpha;
HANDLE_ERROR(cudaMalloc(&gpuAlpha, sizeof(double) * Nl));
HANDLE_ERROR(cudaMemcpy(gpuAlpha, cpuAlpha, sizeof(double) * Nl, cudaMemcpyHostToDevice));
double* gpuI;
HANDLE_ERROR(cudaMalloc(&gpuI, sizeof(double) * nLambda));
//call the kernel to compute the spectrum
dim3 block(BLOCK_SIZE*BLOCK_SIZE);
dim3 grid(nLambda/block.x + 1);
//devComputeSpectrum
devComputeSpectrum<<<grid, block>>>(gpuI, (double2*)gpuB, gpuAlpha, Nl,
nSamples, oThetaI, oThetaO, cThetaI, cThetaO);
HANDLE_ERROR(cudaMemcpy(cpuI, gpuI, sizeof(double) * nLambda, cudaMemcpyDeviceToHost));
HANDLE_ERROR(cudaFree(gpuB));
HANDLE_ERROR(cudaFree(gpuAlpha));
HANDLE_ERROR(cudaFree(gpuI));
|
