mersenne

commit d365c4ddfba0665f4d2c353b65ad62598e36b299
Author: Léo Villeveygoux <l@vgx.fr>
Date:   Fri, 30 Apr 2021 01:13:02 +0200

Just the basic formulas

Diffstat:
A
mersenne.py
 | 
63
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 63 insertions(+), 0 deletions(-)
diff --git a/mersenne.py b/mersenne.py
@@ -0,0 +1,63 @@
+from math import sqrt, pi
+
+notes = {
+    "c"  :  0,
+    "c#" :  1, "db" :  1,
+    "d"  :  2,
+    "d#" :  3, "eb" :  3,
+    "e"  :  4,
+    "f"  :  5,
+    "f#" :  6, "gb" :  6,
+    "g"  :  7,
+    "g#" :  8, "ab" :  8,
+    "a"  :  9,
+    "a#" : 10, "bb" : 10,
+    "b"  : 11
+}
+
+gravity = 9.80665
+# gravity = 9.81
+
+def note_to_freq(note="a", octave=4, basefreq=440):
+    return basefreq * 2 ** (octave-4 + (notes[note]-9)/12)
+
+def radius_to_linear_mass(radius, volumic_mass):
+    return volumic_mass * pi * radius ** 2
+
+def linear_mass_to_radius(linear_mass, volumic_mass):
+    return sqrt(linear_mass / (volumic_mass * pi))
+
+def newton_to_kgf(newton):
+    return newton / gravity
+
+def kgf_to_newton(kgf):
+    return kgf * gravity
+
+# Mersenne's law formulas
+# see https://en.wikipedia.org/wiki/Mersenne%27s_laws
+
+def get_freq(lenght, force, linear_mass):
+    return length * sqrt(force / linear_mass) / 2
+
+def get_force(linear_mass, length, freq):
+    return (2 * freq / length) ** 2 * linear_mass
+
+def get_linear_mass(force, length, freq):
+    return force / (2 * freq / length) ** 2
+
+def get_length(linear_mass, force, freq):
+    return 2 * freq / sqrt(force / linear_mass)
+
+# 
+# def old2_get_tension(freq, length, diameter, density):
+#     mass_lin = (diameter/2/1000)**2 * pi * density
+#     return mass_lin * (2 * freq * length/1000)**2 / gravity
+# 
+# def old_get_tension(freq, length, diameter, density):
+#     return (freq * length/1000 * diameter/1000)**2 * pi * density / gravity
+# 
+# def old_get_diameter(freq, length, density, tension):
+#     return 1000 * sqrt(tension * 9.81 / (pi * density)) / (length/1000 * freq)
+# 
+# def old_get_density(freq, length, diameter, tension):
+#     return tension * gravity / ((freq * length/1000 * diameter/1000)**2 * pi)