go back to using big spectra

bfps/cpp/fluid_solver_base.cpp

@@ -298,17 +298,8 @@ fluid_solver_base<R>::fluid_solver_base( \
     if (this->kM < this->kMy) this->kM = this->kMy; \
     if (this->kM < this->kMz) this->kM = this->kMz; \
     this->kM2 = this->kM * this->kM; \
-    switch(this->dealias_type) \
-    { \
-        case 1: \
-            this->kMspec = 4*this->kM/5; \
-            this->kMspec2 = this->kMspec*this->kMspec; \
-            break; \
-        default: \
     this->kMspec = this->kM; \
     this->kMspec2 = this->kM2; \
-            break; \
-    } \
     this->dk = this->dkx; \
     if (this->dk > this->dky) this->dk = this->dky; \
     if (this->dk > this->dkz) this->dk = this->dkz; \

bfps/fluid_base.py

@@ -361,9 +361,9 @@ class fluid_particle_base(bfps.code):
     def get_kspace(self):
         kspace = {}
         if self.parameters['dealias_type'] == 1:
-            kMx = self.parameters['dkx']*(4*(self.parameters['nx']//2 - 1)//5)
-            kMy = self.parameters['dky']*(4*(self.parameters['ny']//2 - 1)//5)
-            kMz = self.parameters['dkz']*(4*(self.parameters['nz']//2 - 1)//5)
+            kMx = self.parameters['dkx']*(self.parameters['nx']//2 - 1)
+            kMy = self.parameters['dky']*(self.parameters['ny']//2 - 1)
+            kMz = self.parameters['dkz']*(self.parameters['nz']//2 - 1)
         else:
             kMx = self.parameters['dkx']*(self.parameters['nx']//3 - 1)
             kMy = self.parameters['dky']*(self.parameters['ny']//3 - 1)