backpropagation neural network generate identical outputs for different input
<p>I've hit a brick wall with backpropagation neural network and I don't know what might be the problem, please help.</p>

<p>In this sample run, I am using 3 layer ann.</p>

<p>1st layer has 10 input neurons
2nd layer has 7 hidden neurons
3rd layer has 2 output neurons</p>

<p>I am using sigmoid activation function for the hidden neuron, and hyper tangent (i.e tanh) activation function for the output neurons.</p>

<p>In this test, i am using learning rate of 0.1, and momentum constant of 0.01 (I have tried other different combination too, and output still have identical problem).</p>

<p>As show below, the training algorithm stop after n iteration, although, the error is still high.</p>

<p>I am using the data sets below to train, and I also used it to test the network after trained.</p>

<p>I trained the network by mapping all ten input into value between 0 and 1. Simply by taking each input and divide by 5000, and if the result is greater than 1, i set it to be 1. For output, I mapped them to -1 and 1, by divide by 100.</p>

<p>As you can see, the output is identical for different inputs.</p>

<p>Does anyone know what might be the problem?</p>

<p>Your input is most welcome.</p>

<p>Thanks</p>

<p><em><strong></em>**<em>*</em>**</strong><em>sample output</em><strong><em>*</em>**<em>*</em>**<em>*</em></strong></p>

<p>T1 is 0 and ANN output is 0.0904967273528686
T2 is -0.01 and ANN output is -0.399660970430866</p>

<p>T1 is 0 and ANN output is 0.0904967273528686
T2 is -0.14 and ANN output is -0.399660970430866</p>

<p>T1 is 0 and ANN output is 0.0904967273528686
T2 is -0.14 and ANN output is -0.399660970430866</p>

<p>T1 is 0 and ANN output is 0.0904967273528686
T2 is -0.14 and ANN output is -0.399660970430866</p>

<p>T1 is 0 and ANN output is 0.0904967273528686
T2 is -0.24 and ANN output is -0.399660970430866</p>

<p>T1 is 0 and ANN output is 0.0904967273528686
T2 is -0.32 and ANN output is -0.399660970430866</p>

<p>T1 is 0.04 and ANN output is 0.0904967273528686
T2 is -0.32 and ANN output is -0.399660970430866</p>

<p>T1 is 0.04 and ANN output is 0.0904967273528686
T2 is -0.32 and ANN output is -0.399660970430866</p>

<p>T1 is 0.16 and ANN output is 0.0904967273528686
T2 is -0.32 and ANN output is -0.399660970430866</p>

<p>T1 is 0.18 and ANN output is 0.0904967273528686
T2 is -0.32 and ANN output is -0.399660970430866</p>

<p>T1 is 0.18 and ANN output is 0.0904967273528686
T2 is -0.35 and ANN output is -0.399660970430866</p>

<p>T1 is 0.18 and ANN output is 0.0904967273528686
T2 is -0.35 and ANN output is -0.399660970430866</p>

<p><em><strong></em>*</strong><em>sample training data</em><strong><em>*</em>**<em>*</em>**</strong>*and test data after trained
1768,1946,2442,4305,7542,6584,2324,1487,1099,975,0,-1
1767,1946,2444,4309,7551,6575,2318,1483,1100,976,0,-14
1764,1942,2441,4212,7555,6565,2311,1480,1097,972,0,-14
1764,1942,2441,4212,7555,6565,2311,1480,1097,972,0,-14
1762,1944,2445,4339,7571,6500,2302,1478,1095,970,0,-24
1762,1944,2445,4339,7571,6500,2302,1478,1095,970,0,-32
1762,1948,2460,4404,7628,6408,2266,1482,1100,973,4,-32
1762,1948,2460,4404,7628,6408,2266,1482,1100,973,4,-32
1742,1909,2381,4186,7375,6882,2432,1533,1163,999,16,-32
1727,1879,2316,4142,7139,7201,2589,1563,1207,1015,18,-32
1712,1859,2288,4232,7051,7275,2658,1570,1236,1038,18,-35
1712,1859,2288,4232,7051,7275,2658,1570,1236,1038,18,-35
1693,1829,2240,4146,6892,7485,2784,1592,1267,1086,18,-37
1693,1829,2240,4146,6892,7485,2784,1592,1267,1086,16,-40
1669,1802,2199,4229,6766,7528,2966,1624,1282,1126,16,-40
1669,1802,2199,4229,6766,7528,2966,1624,1282,1126,16,-40
1669,1802,2199,4229,6766,7528,2966,1624,1282,1126,16,-40
1648,1772,2153,4301,6602,7608,3244,1681,1289,1160,14,-40
1648,1772,2153,4301,6602,7608,3244,1681,1289,1160,4,-40
1648,1772,2153,4301,6602,7608,3244,1681,1289,1160,4,-40
1640,1790,2217,4722,7082,7233,2860,1612,1249,1159,4,-40
1632,1788,2227,5122,7214,7055,2698,1603,1249,1140,4,-40
1632,1788,2227,5122,7214,7055,2698,1603,1249,1140,4,-40
1621,1782,3170,4590,7293,4816,2829,1608,1257,1118,4,-40
1621,1782,3170,4590,7293,4816,2829,1608,1257,1118,4,-40
1616,1780,4302,3004,6751,6844,2860,1606,1262,1121,4,-40
1616,1780,4302,3004,6751,6844,2860,1606,1262,1121,4,-40
1616,1780,4302,3004,6751,6844,2860,1606,1262,1121,4,-40
1592,1025,5023,3609,7446,6739,2852,1602,1265,1125,4,-40
1592,1025,5023,3609,7446,6739,2852,1602,1265,1125,4,-40
1592,1025,5023,3609,7446,6739,2852,1602,1265,1125,4,-40
1604,1779,5664,3645,7522,6605,2863,1595,1264,1124,4,-40
1601,1945,6094,3701,7592,6487,2918,1590,1262,1127,7,-40
1587,3426,5418,3561,7437,6662,3140,1626,1288,1142,7,-40
1587,3426,5418,3561,7437,6662,3140,1626,1288,1142,7,-40
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,7,-40
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,7,-40
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,7,-40
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,7,-40
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,7,-40
2795,7097,2235,3606,7513,6514,3412,1634,1305,1165,7,-40
2795,7097,2235,3606,7513,6514,3412,1634,1305,1165,7,-40
4374,5780,2240,3635,7554,6458,3337,2228,1306,1169,7,-40
4374,5780,2240,3635,7554,6458,3337,2228,1306,1169,7,-40
4374,5780,2240,3635,7554,6458,3337,2228,1306,1169,7,-40
6657,2127,2247,3679,7613,6373,3085,3845,1307,1173,7,-40
5794,1755,2249,3691,7632,6333,2983,5134,1300,1175,9,-40
4045,1735,2208,3576,7510,6527,2932,4549,3576,1188,9,-40
4045,1735,2208,3576,7510,6527,2932,4549,3576,1188,9,-40
4045,1735,2208,3576,7510,6527,2932,4549,3576,1188,9,-40
4045,1735,2208,3576,7510,6527,2932,4549,3576,1188,9,-40
1543,1725,2194,3556,7501,6556,2787,2384,8183,1484,9,-40
1534,1718,2183,3534,7483,6590,2713,2255,6696,3743,9,-40
1529,1709,2171,3508,7461,6636,2673,2143,5150,5561,9,-40
1525,1705,2162,3492,7446,6673,2659,2042,3743,7173,9,-40
1525,1705,2162,3492,7446,6673,2659,2042,3743,7173,9,-40
1524,1704,2160,3487,7443,6677,2660,2023,3561,7348,9,-40
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,9,-40
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,9,-40
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,9,-40
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,9,-40
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,9,-40
1508,1677,2122,3425,7400,6764,2702,1741,1585,1947,9,-40
1508,1677,2122,3425,7400,6764,2702,1741,1585,1947,9,-40
1505,1672,2119,3415,7401,6772,2709,1756,1476,1659,9,-40
1505,1672,2119,3415,7401,6772,2709,1756,1476,1659,9,-40
1505,1672,2119,3415,7401,6772,2709,1756,1476,1659,9,-40
1505,1672,2119,3415,7401,6772,2709,1756,1476,1659,9,-40
1483,1652,2093,3370,7356,6817,2789,1723,1409,1308,9,-40
1477,1648,2085,3357,7348,6837,2830,1704,1418,1267,9,-40
1476,1642,2076,3337,7323,6866,2873,1705,1416,1276,9,-40
1476,1642,2076,3337,7323,6866,2873,1705,1416,1276,9,-40
1476,1642,2076,3337,7323,6866,2873,1705,1416,1276,9,-40
1472,1638,2073,3336,7329,6862,2888,1730,1395,1282,9,-40
1461,1626,2057,3314,7311,6879,2900,1759,1369,1285,9,-40
1461,1626,2056,3314,7310,6880,2902,1764,1370,1284,9,-40
1458,1621,2052,3304,7311,6891,2915,1792,1382,1262,9,-40
1453,1616,2043,3292,7302,6908,2929,1821,1386,1250,9,-40
1444,1609,2034,3275,7285,6931,2952,1846,1416,1259,9,-40
1443,1610,2036,3278,7287,6924,2947,1847,1418,1261,9,-40
1440,1606,2031,3277,7297,6916,2944,1846,1435,1263,9,-40
1432,1597,2017,3248,7265,6954,2971,1858,1469,1272,9,-40
1432,1597,2017,3248,7265,6954,2971,1858,1469,1272,9,-40
1431,1591,2013,3247,7265,6948,2974,1863,1476,1298,9,-40
1431,1591,2013,3247,7265,6948,2974,1863,1476,1298,9,-40
1428,1587,2008,3240,7263,6947,2982,1870,1483,1326,7,-6</p>

<hr>

<p>As for caution, I thought the training data might have too many similar outputs, so i manually altered some of the output to make it more realistic; and the problem of identical output still there.</p>

<p>here is my altered training data sets,</p>

<p>1768,1946,2442,4305,7542,6584,2324,1487,1099,975,-1,-6
1767,1946,2444,4309,7551,6575,2318,1483,1100,976,0,-44
1764,1942,2441,4212,7555,6565,2311,1480,1097,972,1,-54
1764,1942,2441,4212,7555,6565,2311,1480,1097,972,3,-44
1762,1944,2445,4339,7571,6500,2302,1478,1095,970,3,-24
1762,1944,2445,4339,7571,6500,2302,1478,1095,970,-2,-32
1762,1948,2460,4404,7628,6408,2266,1482,1100,973,4,-32
1762,1948,2460,4404,7628,6408,2266,1482,1100,973,4,-32
1742,1909,2381,4186,7375,6882,2432,1533,1163,999,16,-32
1727,1879,2316,4142,7139,7201,2589,1563,1207,1015,18,-32
1712,1859,2288,4232,7051,7275,2658,1570,1236,1038,22,-35
1712,1859,2288,4232,7051,7275,2658,1570,1236,1038,20,-35
1693,1829,2240,4146,6892,7485,2784,1592,1267,1086,30,-37
1693,1829,2240,4146,6892,7485,2784,1592,1267,1086,15,-40
1669,1802,2199,4229,6766,7528,2966,1624,1282,1126,16,-60
1669,1802,2199,4229,6766,7528,2966,1624,1282,1126,17,-50
1669,1802,2199,4229,6766,7528,2966,1624,1282,1126,18,-30
1648,1772,2153,4301,6602,7608,3244,1681,1289,1160,19,-10
1648,1772,2153,4301,6602,7608,3244,1681,1289,1160,3,-80
1648,1772,2153,4301,6602,7608,3244,1681,1289,1160,-3,-90
1640,1790,2217,4722,7082,7233,2860,1612,1249,1159,2,-70
1632,1788,2227,5122,7214,7055,2698,1603,1249,1140,-2,-40
1632,1788,2227,5122,7214,7055,2698,1603,1249,1140,4,-40
1621,1782,3170,4590,7293,4816,2829,1608,1257,1118,-4,-20
1621,1782,3170,4590,7293,4816,2829,1608,1257,1118,6,-40
1616,1780,4302,3004,6751,6844,2860,1606,1262,1121,-6,-10
1616,1780,4302,3004,6751,6844,2860,1606,1262,1121,5,-40
1616,1780,4302,3004,6751,6844,2860,1606,1262,1121,-5,-50
1592,1025,5023,3609,7446,6739,2852,1602,1265,1125,2,-40
1592,1025,5023,3609,7446,6739,2852,1602,1265,1125,-2,-60
1592,1025,5023,3609,7446,6739,2852,1602,1265,1125,1,-70
1604,1779,5664,3645,7522,6605,2863,1595,1264,1124,-1,-80
1601,1945,6094,3701,7592,6487,2918,1590,1262,1127,5,-40
1587,3426,5418,3561,7437,6662,3140,1626,1288,1142,6,-40
1587,3426,5418,3561,7437,6662,3140,1626,1288,1142,7,-60
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,8,-40
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,4,-60
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,3,-40
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,2,-60
1581,5498,4155,3570,7458,6616,3251,1632,1296,1153,1,-40
2795,7097,2235,3606,7513,6514,3412,1634,1305,1165,2,-50
2795,7097,2235,3606,7513,6514,3412,1634,1305,1165,3,-40
4374,5780,2240,3635,7554,6458,3337,2228,1306,1169,4,-80
4374,5780,2240,3635,7554,6458,3337,2228,1306,1169,5,-40
4374,5780,2240,3635,7554,6458,3337,2228,1306,1169,6,-90
6657,2127,2247,3679,7613,6373,3085,3845,1307,1173,-7,-40
5794,1755,2249,3691,7632,6333,2983,5134,1300,1175,-6,-90
4045,1735,2208,3576,7510,6527,2932,4549,3576,1188,-5,-40
4045,1735,2208,3576,7510,6527,2932,4549,3576,1188,-4,-70
4045,1735,2208,3576,7510,6527,2932,4549,3576,1188,-3,-40
4045,1735,2208,3576,7510,6527,2932,4549,3576,1188,-2,-30
1543,1725,2194,3556,7501,6556,2787,2384,8183,1484,-1,-30
1534,1718,2183,3534,7483,6590,2713,2255,6696,3743,0,-40
1529,1709,2171,3508,7461,6636,2673,2143,5150,5561,1,-40
1525,1705,2162,3492,7446,6673,2659,2042,3743,7173,2,-50
1525,1705,2162,3492,7446,6673,2659,2042,3743,7173,3,-40
1524,1704,2160,3487,7443,6677,2660,2023,3561,7348,4,-50
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,5,-40
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,6,-50
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,7,-40
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,8,-40
1521,1701,2155,3478,7434,6702,2662,1919,1940,8149,9,-60
1508,1677,2122,3425,7400,6764,2702,1741,1585,1947,8,-40
1508,1677,2122,3425,7400,6764,2702,1741,1585,1947,7,-70
1505,1672,2119,3415,7401,6772,2709,1756,1476,1659,6,-40
1505,1672,2119,3415,7401,6772,2709,1756,1476,1659,5,-80
1505,1672,2119,3415,7401,6772,2709,1756,1476,1659,4,-40
1505,1672,2119,3415,7401,6772,2709,1756,1476,1659,3,-70
1483,1652,2093,3370,7356,6817,2789,1723,1409,1308,2,-40
1477,1648,2085,3357,7348,6837,2830,1704,1418,1267,1,-70
1476,1642,2076,3337,7323,6866,2873,1705,1416,1276,0,-40
1476,1642,2076,3337,7323,6866,2873,1705,1416,1276,-1,-50
1476,1642,2076,3337,7323,6866,2873,1705,1416,1276,-2,-40
1472,1638,2073,3336,7329,6862,2888,1730,1395,1282,-3,-90
1461,1626,2057,3314,7311,6879,2900,1759,1369,1285,-4,-40
1461,1626,2056,3314,7310,6880,2902,1764,1370,1284,-5,-90
1458,1621,2052,3304,7311,6891,2915,1792,1382,1262,-6,-40
1453,1616,2043,3292,7302,6908,2929,1821,1386,1250,-7,-90
1444,1609,2034,3275,7285,6931,2952,1846,1416,1259,-8,-40
1443,1610,2036,3278,7287,6924,2947,1847,1418,1261,-9,-70
1440,1606,2031,3277,7297,6916,2944,1846,1435,1263,-8,-40
1432,1597,2017,3248,7265,6954,2971,1858,1469,1272,-7,-80
1432,1597,2017,3248,7265,6954,2971,1858,1469,1272,-6,-40
1431,1591,2013,3247,7265,6948,2974,1863,1476,1298,-5,-50
1431,1591,2013,3247,7265,6948,2974,1863,1476,1298,-4,-40
1428,1587,2008,3240,7263,6947,2982,1870,1483,1326,-3,-60</p>
