#Latin hypercube sampling code
#Function: To produce a random Latin hypercube sample that
#can then be used for sensitivity and
#uncertainty analysis.
#
import random
import math
import string

def rdcsv(name):
    f = open(name,"r")
    data = []
    tmp = f.readline()
    while tmp !="":
        onerow = tmp.split(",")
        last = len(onerow)-1
        k = len(onerow[last])
        if k!= 1:
           onerow[last] = onerow[last][0:k-1]
        if len(onerow) !=  0:
           data.append(onerow)
        tmp = f.readline()
    f.close()
    return(data)

def outcsv(name,data):
    f = open(name,"w")
    for i in range(0,len(data)):
        tmp = ""
        for j in range(0,len(data[i])):
            tmp = tmp + str(data[i][j]) + ","
        tmp = tmp[0:len(tmp)-1]+"\n"        
        f.writelines(tmp)
    f.close()

def trunc(x,n):
    a = x * 10 **n
    a = math.floor(a)
    return(float(a)/10**n)

#Get information on parameters and ranges from user file

filename = raw_input("Enter parameter range file name: ")

params = rdcsv(filename)
#format is:
#param-name,low,high

#set dimension
k=len(params)

#set num of intervals
#which is also the number of samples to draw
n=int(raw_input("Enter number of samples to draw: "))

names=[]
for i in range(0,k):
    names.append(params[i][0])

pranges=[]
for i in range(0,k):
    tmp=[names[i]]
    low=float(params[i][1])
    high=float(params[i][2])
    delta=(high-low)/float(n)
    for j in range(0,n):
        tmp.append(random.uniform(low+j*delta,low+(j+1)*delta))
    pranges.append(tmp)
     
if (n<math.ceil(4.0/3.0*k)):
    print "n is too small"

s=[]
for i in range(0,k):
    s.append(range(0,n))

result=[]
for i in range(0,n):
    tmp=[]
    for j in range(0,k):
        a = random.sample(s[j],1)[0]
        #print a,s[j]
        tmp.append(a)
        s[j].remove(a)
    result.append(tmp)

#output hypercube
print "The random Latin hypercube is:\n\n"
print names
for i in range(0,len(result)):
   print result[i]

#Get the parameter values that we should be using now...
#Dereference the result list using the pranges list
print "The parameter array that should be used is:\n\n"
sample=[names]
for l in range(0,len(result)):
    tmp=[]
    for j in range(0,len(result[l])):
        tmp.append(pranges[j][result[l][j]+1])
    sample.append(tmp)

for i in range(0,len(sample)):
    print sample[i]

outname=raw_input("Enter output filename: ")
numdec=int(raw_input("Enter number of decimal places desired: "))
for i in range(1,len(sample)):
    for j in range(0,len(sample[i])):
        sample[i][j]=trunc(sample[i][j],numdec)

outcsv(outname,sample)