def beta_pdf(x, a, b):
bc = <NUM_LIT:1> / beta(a, b)<EOL>fc = x ** (a - <NUM_LIT:1>)<EOL>sc = (<NUM_LIT:1> - x) ** (b - <NUM_LIT:1>)<EOL>return bc * fc * sc<EOL>
Beta distirbution probability density function.