func (b *thermField) update() {
// we need to fix the time step here because solver will not yet have done it before the first step.
// FixDt as an lvalue that sets Dt_si on change might be cleaner.
if FixDt != 0 {
Dt_si = FixDt
}
if b.generator == 0 {
b.generator = curand.CreateGenerator(curand.PSEUDO_DEFAULT)
b.generator.SetSeed(b.seed)
}
if b.noise == nil {
b.noise = cuda.NewSlice(b.NComp(), b.Mesh().Size())
// when noise was (re-)allocated it's invalid for sure.
B_therm.step = -1
B_therm.dt = -1
}
if Temp.isZero() {
cuda.Memset(b.noise, 0, 0, 0)
b.step = NSteps
b.dt = Dt_si
return
}
// keep constant during time step
if NSteps == b.step && Dt_si == b.dt {
return
}
if FixDt == 0 {
util.Fatal("Finite temperature requires fixed time step. Set FixDt != 0.")
}
N := Mesh().NCell()
k2_VgammaDt := 2 * mag.Kb / (GammaLL * cellVolume() * Dt_si)
noise := cuda.Buffer(1, Mesh().Size())
defer cuda.Recycle(noise)
const mean = 0
const stddev = 1
dst := b.noise
ms := Msat.MSlice()
defer ms.Recycle()
temp := Temp.MSlice()
defer temp.Recycle()
alpha := Alpha.MSlice()
defer alpha.Recycle()
for i := 0; i < 3; i++ {
b.generator.GenerateNormal(uintptr(noise.DevPtr(0)), int64(N), mean, stddev)
cuda.SetTemperature(dst.Comp(i), noise, k2_VgammaDt, ms, temp, alpha)
}
b.step = NSteps
b.dt = Dt_si
}
func (g *geom) Slice() (*data.Slice, bool) {
s := g.Gpu()
if s.IsNil() {
s := cuda.Buffer(g.NComp(), g.Mesh().Size())
cuda.Memset(s, 1)
return s, true
} else {
return s, false
}
}
func (d *constValue) EvalTo(dst *data.Slice) {
for c, v := range d.value {
cuda.Memset(dst.Comp(c), float32(v))
}
}