subtotals are not displayed

dear experts,

I tried the BELOW CODE-LINES in alv report to display the TOTALS and SUBTOTALS , but anyhow the 'SUMMATION AND SUBTOTALING ' signs are not comming in the display and I couldn't calculate them.

DATA: I_FIELDCAT TYPE SLIS_T_FIELDCAT_ALV,

W_FIELDCAT TYPE SLIS_FIELDCAT_ALV.

DATA:wa_sortinfo TYPE slis_sortinfo_alv,

t_sort_info TYPE slis_t_sortinfo_alv.

DATA: W_LAYOUT TYPE SLIS_LAYOUT_ALV.

FORM BUILD_FIELDCATALOG.

W_FIELDCAT-TABNAME = 'I_FINAL'.

W_FIELDCAT-FIELDNAME = 'MATNR'.

W_FIELDCAT-SELTEXT_M = 'MAT NO'.

W_FIELDCAT-COL_POS = 1.

W_FIELDCAT-OUTPUTLEN = 8.

W_FIELDCAT-DO_SUM = 'X'.

W_FIELDCAT-SP_GROUP = 'X'.

APPEND W_FIELDCAT TO I_FIELDCAT.

CLEAR W_FIELDCAT.

W_FIELDCAT-TABNAME = 'I_FINAL'.

W_FIELDCAT-FIELDNAME = 'ERNAM'.

W_FIELDCAT-SELTEXT_M = 'PERSON NAME'.

W_FIELDCAT-COL_POS = 2.

W_FIELDCAT-OUTPUTLEN = 15.

W_FIELDCAT-DO_SUM = 'X'.

W_FIELDCAT-SP_GROUP = 'X'.

APPEND W_FIELDCAT TO I_FIELDCAT.

CLEAR W_FIELDCAT.

W_FIELDCAT-TABNAME = 'I_FINAL'.

W_FIELDCAT-FIELDNAME = 'WERKS'.

W_FIELDCAT-SELTEXT_M = 'PLANTS'.

W_FIELDCAT-COL_POS = 4.

W_FIELDCAT-OUTPUTLEN = 20.

W_FIELDCAT-DO_SUM = 'X'.

W_FIELDCAT-SP_GROUP = 'X'.

APPEND W_FIELDCAT TO I_FIELDCAT.

CLEAR W_FIELDCAT.

ENDFORM.

FORM DATA_SORT USING SORTINFO TYPE SLIS_T_SORTINFO_ALV.

CLEAR SORTINFO.

WA_SORTINFO-TABNAME = 'I_FINAL'.

WA_SORTINFO-FIELDNAME = 'MATNR'.

WA_SORTINFO-DOWN = C_X.

WA_SORTINFO-SUBTOT = 'X'.

APPEND WA_SORTINFO TO SORTINFO.

CLEAR WA_SORTINFO.

WA_SORTINFO-TABNAME = 'I_FINAL'.

WA_SORTINFO-FIELDNAME = 'ERNAM'.

WA_SORTINFO-DOWN = C_X.

WA_SORTINFO-SUBTOT = 'X'.

APPEND WA_SORTINFO TO SORTINFO.

CLEAR WA_SORTINFO.

WA_SORTINFO-TABNAME = 'I_FINAL'.

WA_SORTINFO-FIELDNAME = 'WERKS'.

WA_SORTINFO-DOWN = C_X.

WA_SORTINFO-SUBTOT = 'X'.

APPEND WA_SORTINFO TO SORTINFO.

CLEAR WA_SORTINFO.

ENDFORM. " DATA_SORT

FORM BUILD_LAYOUT .

W_LAYOUT-TOTALS_TEXT = 'TOTALS'.

W_LAYOUT-SUBTOTALS_TEXT = 'SUBTOTALS'.

w_layout-colwidth_optimize = 'X'.

*w_layout-totals_only = 'X'.

w_layout-no_input = 'X'.

*w_layout-no_subtotals = space.

ENDFORM. " BUILD_LAYOUT

I have passed all the 'I_FIELDCAT[ ], W_LAYOUT and T_SORT_INFO' in 'REUSE_ALV_GRID_DISPLAY',

but it didn't work.

PLEASE HELP.