diff --git a/cuslines/cuda_c/generate_streamlines_cuda.cu b/cuslines/cuda_c/generate_streamlines_cuda.cu
index 68c32d0..9b9462f 100644
--- a/cuslines/cuda_c/generate_streamlines_cuda.cu
+++ b/cuslines/cuda_c/generate_streamlines_cuda.cu
@@ -148,7 +148,7 @@ __device__ int get_direction_prob_d(curandStatePhilox4_32_10_t *st,
                                            dir.y*sphere_vertices[i].y+
                                            dir.z*sphere_vertices[i].z;
 
-                        if (FABS(dot) < cos_similarity) {
+                        if (APPLY_ABS_IF_SYM(dot) < cos_similarity) {
                                 __pmf_data_sh[i] = 0.0;
                         }
                 }
diff --git a/cuslines/cuda_c/globals.h b/cuslines/cuda_c/globals.h
index 505f5cc..31017b6 100644
--- a/cuslines/cuda_c/globals.h
+++ b/cuslines/cuda_c/globals.h
@@ -67,6 +67,12 @@
 
 #endif
 
+#if FULL_BASIS == 1
+  #define APPLY_ABS_IF_SYM(x) (x)
+#else
+  #define APPLY_ABS_IF_SYM(x) FABS(x)
+#endif
+
 #define MIN(x,y) (((x)<(y))?(x):(y))
 #define MAX(x,y) (((x)>(y))?(x):(y))
 #define POW2(n) (1 << (n))
diff --git a/cuslines/cuda_c/tracking_helpers.cu b/cuslines/cuda_c/tracking_helpers.cu
index b9d9e20..f5b2569 100644
--- a/cuslines/cuda_c/tracking_helpers.cu
+++ b/cuslines/cuda_c/tracking_helpers.cu
@@ -206,9 +206,10 @@ __device__ int peak_directions_d(const REAL_T  *__restrict__ odf,
 
                                 int j = 0;
                                 for(; j < k; j++) {
-                                        const REAL_T cos = FABS(abc.x*dirs[j].x+
-                                                                abc.y*dirs[j].y+
-                                                                abc.z*dirs[j].z);
+                                        const REAL_T cos = APPLY_ABS_IF_SYM(
+                                                abc.x*dirs[j].x+
+                                                abc.y*dirs[j].y+
+                                                abc.z*dirs[j].z);
                                         if (cos > cos_similarity) {
                                                 break;
                                         }
diff --git a/cuslines/cuda_python/cu_direction_getters.py b/cuslines/cuda_python/cu_direction_getters.py
index 466c0e0..54adb9e 100644
--- a/cuslines/cuda_python/cu_direction_getters.py
+++ b/cuslines/cuda_python/cu_direction_getters.py
@@ -82,6 +82,7 @@ def compile_program(self, gpu_tracker, debug: bool = False):
             "RNG_SEED": str(int(gpu_tracker.rng_seed)),
             "SAMPLM_NR": str(int(gpu_tracker.samplm_nr)),
             "NUM_EDGES": str(int(gpu_tracker.nedges)),
+            "FULL_BASIS": "1" if gpu_tracker.full_basis else "0",
             "EXCESS_ALLOC_FACT": str(int(EXCESS_ALLOC_FACT)),
             "MAX_SLINES_PER_SEED": str(int(MAX_SLINES_PER_SEED)),
             "MAX_SLINE_LEN": str(int(MAX_SLINE_LEN)),
diff --git a/cuslines/cuda_python/cu_tractography.py b/cuslines/cuda_python/cu_tractography.py
index ebee530..1f0afcb 100644
--- a/cuslines/cuda_python/cu_tractography.py
+++ b/cuslines/cuda_python/cu_tractography.py
@@ -40,6 +40,7 @@ def __init__(
         stop_threshold: float,
         sphere_vertices: np.ndarray,
         sphere_edges: np.ndarray,
+        full_basis: bool = False,
         max_angle: float = radians(60),
         step_size: float = 0.5,
         min_pts=0,
@@ -70,6 +71,9 @@ def __init__(
             Vertices of the sphere used for direction sampling.
         sphere_edges : np.ndarray
             Edges of the sphere used for direction sampling.
+        full_basis : bool, optional
+            Whether to use full basis for spherical harmonics
+            default: False
         max_angle : float, optional
             Maximum angle (in radians) between steps
             default: radians(60)
@@ -143,6 +147,7 @@ def __init__(
         self.rng_seed = int(rng_seed)
         self.rng_offset = int(rng_offset)
         self.chunk_size = int(chunk_size)
+        self.full_basis = bool(full_basis)
 
         avail = checkCudaErrors(runtime.cudaGetDeviceCount())
         if self.ngpus > avail: