[mesias]

I Want to share this PostgreSQL Function

-- Function: irr_calculate(double precision[])

-- DROP FUNCTION irr_calculate(double precision[]);

-- Just enter cash flow to use this function
CREATE OR REPLACE FUNCTION irr_calculate(cashflows double precision[])
  RETURNS double precision AS
$BODY$
DECLARE
    epsilon double precision := 0.00001; -- The desired level of precision
    max_iterations integer := 100; -- Maximum number of iterations
    guess double precision := 0.1; -- Initial initialization for IRR
    irr double precision := 0.0; -- Initialize IRR to 0
    npv double precision;
    derivative double precision;
BEGIN
    FOR i IN 1..max_iterations LOOP
        npv := 0.0;
        derivative := 0.0;
       
        FOR j IN 1..array_length(cashflows, 1) LOOP
            npv := npv + cashflows[j] / power(1.0 + irr, j - 1);
            derivative := derivative - j * cashflows[j] / power(1.0 + irr, j);
        END LOOP;
       
        irr := irr - npv / derivative;
       
        IF abs(npv) < epsilon THEN
            RETURN irr * 100.0;
        END IF;
    END LOOP;
   
    RAISE EXCEPTION 'The IRR calculation did not found';
END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION irr_calculate(double precision[])
  OWNER TO postgres;