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# Drug Dosage Model for Math 311
# Mark Goadrich Spring 2009
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fout = open("drugStomach.csv", "w")

# Initialize parameters
simLength = 10
populationS = 100
populationB = 0
growthRate = -0.1
stToBloodRate = 0.05
bloodToOrganRate = 0.1
intervalSize = 0.25  # decrease to approximate continuous growth
growthRatePerStep = growthRate * intervalSize

# Iterate through simulation
for i in range(int(simLength / intervalSize)):
    populationS_next = populationS + growthRatePerStep * populationS - populationS * stToBloodRate
    populationB_next = populationB + stToBloodRate * populationS - populationB * bloodToOrganRate
    populationS = populationS_next
    populationB = populationB_next
    fout.write("%f, %f, %f\n" % (i*intervalSize, populationS, populationB))

fout.close()