Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

LUT help!!!

I have wrote this code for implementing a neural network.What it does is to take some values(inputs) and some weights and computes the SUM(values*weigths).What i want to do is to check if the total sum(values*weights)< threshold and correct the weights in order to sum(values*weights)>=threshold.I think that i have to store the weights on a look up table and change the values in order to sum(values*weights)>=threshold.How i can do this?.My code is :

LIBRARY IEEE;

USE IEEE.STD_LOGIC_1164.ALL;

USE IEEE.STD_LOGIC_ARITH.ALL;

USE IEEE.STD_LOGIC_UNSIGNED.ALL;

USE IEEE.STD_LOGIC_SIGNED.ALL;

ENTITY ANN IS

GENERIC ( m : INTEGER := 4; -- Number of inputs or weights

b : INTEGER := 8); --Number of bits per input or weight

PORT ( x1,x2,x3,x4: IN UNSIGNED(b-1 DOWNTO 0);

w : IN UNSIGNED(b-1 DOWNTO 0);

clk: IN STD_LOGIC;

y : buffer UNSIGNED(2*b-1 DOWNTO 0);

id : buffer bit);

END ANN;

ARCHITECTURE NEURAL OF ANN IS

TYPE weights IS ARRAY (1 TO m) OF UNSIGNED(b-1 DOWNTO 0);

TYPE inputs IS ARRAY (1 TO m) OF UNSIGNED(b-1 DOWNTO 0);

BEGIN

PROCESS(clk,w,x1,x2,x3,x4)

VARIABLE weight : weights;

VARIABLE input : inputs;

VARIABLE prod,acc : UNSIGNED(2*b-1 DOWNTO 0);

VARIABLE sub : UNSIGNED(2*b-1 DOWNTO 0);

BEGIN

IF (clk'EVENT AND CLK='1') THEN

weight:=w&weight(1 TO m-1);

END IF;

input(1):=x1;

input(2):=x2;

input(3):=x3;

input(4):=x4;

acc:=(OTHERS=>'0');

FOR j IN 1 TO m LOOP

prod:=input(j)*weight(j);

acc:=acc+prod;

END LOOP;

y<=acc;

END IF;

END PROCESS;

END NEURAL;

70 Replies

Show More
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    Ok i will try to implement it and i will write my feedback tommorow.I hope will find you online to help me.Thank you very much

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    Ok i manage to do the first part of the project.What it does is :i insert some values for inputs(that will remain constants through all the process) and then when a clock EVENT i do this computation : input1*weight1+input2*weight2+input3*weight3.This is the multiply-accumulator unit.The second thing that i want to do(for which i need your help) is to compare this result(from the previous step) with a threshold and then fix the weight values in order to :

    input1*weight1(new)+input2*weight2(new)+input3*weight3(new)>threshold.Here is my code

    library ieee;

    use ieee.std_logic_1164.all;

    use ieee.std_logic_unsigned.all;

    use ieee.std_logic_arith.all;

    entity neuron is

    port ( in1,in2,in3,w1,w2,w3 : in unsigned (7 downto 0);

    clk : in std_logic;

    id : out bit;

    output : out unsigned (15 downto 0));

    end neuron;

    architecture behavioral of neuron is

    type inputs is array (1 to 3) of unsigned (7 downto 0);

    type weights is array (1 to 3) of unsigned (7 downto 0);

    constant threshold : unsigned(15 downto 0):="0000011011100111";

    constant sum : unsigned:="1";

    begin

    process(clk,w1,w2,w3)

    variable weight : weights;

    variable input : inputs;

    variable prod,acc : unsigned (15 downto 0);

    begin

    if(clk'EVENT AND clk='1') then

    input(1):=in1;

    input(2):=in2;

    input(3):=in3;

    weight(1):=w1;

    weight(2):=w2;

    weight(3):=w3;

    acc:=(others=>'0');

    end if;

    for j in 1 to 3 loop

    prod:=input(j)*weight(j);

    acc:=acc+prod;

    end loop;

    if(acc>threshold) then id<='1';

    else id<='0';

    end if;

    output<=acc;

    end process;

    end behavioral;

    I attached and a photo with the simulation results
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    I still think you need to read up on logic design. And stop using variables like you are - you're making it do a lot of work in 1 clock cycle!

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    At least this code does what i want to do?Is it correct from the view of behavior?

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    Yes it does behave correctly.

    I just dont think it will work on a real FPGA, because it is not pipelined.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    To be honest the purpose of my project is to write some code that implements the thing i described in earlier posts.So i suppose it's ok.I will post the code that wrote for the weights update method.Thanks again

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    I wrote this code.What i need to do is to insert 4 values at each clock which i store on a 2-dimensional array and i want to compute the sum of these values.

    LIBRARY IEEE;

    USE IEEE.STD_LOGIC_1164.ALL;

    USE IEEE.STD_LOGIC_ARITH.ALL;

    ENTITY test IS

    PORT( x1 : IN INTEGER RANGE 0 TO 255;

    clk,load : IN STD_LOGIC;

    output1 : out INTEGER RANGE 0 TO 1020);

    END test;

    ARCHITECTURE behavioral OF test IS

    TYPE windows IS ARRAY(0 TO 1,0 to 1) OF INTEGER RANGE 0 TO 255;

    BEGIN

    PROCESS(clk,x1)

    VARIABLE window : windows;

    VARIABLE sum : INTEGER RANGE 0 TO 1020;

    BEGIN

    IF(clk'EVENT AND clk='1') THEN

    IF(load='1') THEN

    FOR i IN 0 TO 1 LOOP

    FOR j IN 0 TO 1 LOOP

    window(i,j):=x1;

    sum:=sum+window(i,j);

    END LOOP;

    END LOOP;

    END IF;

    END IF;

    output1<=sum;

    END PROCESS;

    END behavioral;

    The code has no problem while compiling but in the simulation the results are wrong!!!.Please help.I set in the simulation for the x1 to take 2 values per clock but the result shows that something is wrong.