Added more features to the IC-Builder

Author: TimGoTheCreator

tools/icbuilder.py

@@ -63,4 +63,74 @@ def disk(N, radius=10.0, mass=1.0, thickness=0.1):
 
         particles.append((x, y, z, vx, vy, vz, mass / N))
 
+    return particles
+
+def hernquist(N, scale=1.0, mass=1.0):
+    """
+    Generates a Hernquist sphere with scale radius 'scale' and total mass 'mass'.
+    Velocities are set to zero (cold start).
+    """
+    particles = []
+    M = mass
+    a = scale
+
+    for _ in range(N):
+        # Sample radius from Hernquist distribution
+        u = random.random()
+        r = a * math.sqrt(u) / (1 - math.sqrt(u))
+
+        # Random isotropic angles
+        theta = math.acos(2*random.random() - 1)
+        phi = 2 * math.pi * random.random()
+
+        # Convert to Cartesian
+        x = r * math.sin(theta) * math.cos(phi)
+        y = r * math.sin(theta) * math.sin(phi)
+        z = r * math.cos(theta)
+
+        particles.append((x, y, z, 0, 0, 0, M / N))
+
+    return particles
+
+def rotate_z(x, y, z, angle):
+    ca = math.cos(angle)
+    sa = math.sin(angle)
+    return (ca*x - sa*y, sa*x + ca*y, z)
+
+def two_galaxies(
+    N1, R1, M1, scale1,
+    N2, R2, M2, scale2,
+    angle_deg=0.0,
+    v_rel=1.0
+):
+    """
+    Builds a two-galaxy merger:
+    - Galaxy 1: Hernquist sphere at (-R1, 0, 0)
+    - Galaxy 2: Hernquist sphere at (+R2, 0, 0), rotated by angle_deg
+    - v_rel: relative velocity along y-axis
+    """
+
+    g1 = hernquist(N1, scale1, M1)
+    g2 = hernquist(N2, scale2, M2)
+
+    angle = math.radians(angle_deg)
+    particles = []
+
+    # Galaxy 1: shift left, give velocity +v_rel/2
+    for (x, y, z, vx, vy, vz, m) in g1:
+        particles.append((
+            x - R1, y, z,
+            vx, vy + v_rel/2, vz,
+            m
+        ))
+
+    # Galaxy 2: rotate, shift right, give velocity -v_rel/2
+    for (x, y, z, vx, vy, vz, m) in g2:
+        xr, yr, zr = rotate_z(x, y, z, angle)
+        particles.append((
+            xr + R2, yr, zr,
+            vx, vy - v_rel/2, vz,
+            m
+        ))
+
     return particles