//1 count the number of rows and columns
nRows = phi2.getRowCount()
nCols = phi2.getColumnCount()

//2 get arrays containing values for light, phi2, and reflectance
phi2_vals = phi2.getValueMatrix()
size_vals = size.getValueMatrix()
light_vals = phi2.getExtraRowValues( "light_intensity" )

//3 create an array containing delta-times for each column
times = phi2.getTimeLabels()
dt = new Array(nCols)
for( col = 1 ; col < nCols ; col++ ) {
    dt[col] = times[col]-times[col-1]
}
dt[0] = dt[1]

//4 create an empty 2D array that will eventually contain computed LEF values
totalP_vals = new Array(nRows)
for ( row = 0 ; row < nRows ; row++) {
    totalP_vals[row] = new Array(nCols)
}

//5 iterate through each cell in the phi2 data
for ( row = 0; row < nRows; row++) {
    for ( col = 0; col < nCols; col++) {

        //6 get the phi2, size, light, and delta-time values for this cell
        phi2_cell = phi2_vals[row][col]
        size_cell = size_vals[row][col]
        light_cell = light_vals[col]
        dt_cell = dt[col]
        

        //7 compute totalP for this cell and add it to the result array (as a cumulative)
        totalP_cell = phi2_cell * light_cell * .42 * size_cell * dt_cell
        totalP_vals[row][col] = totalP_cell
        if( col > 0 )
            totalP_vals[row][col] += totalP_vals[row][col-1]
    }
}

//8 display a total photosynthesis heatmap using the same times, and row labels as phi2
row_labels = phi2.getRowLabels(true)
totalP = new Heatmap( row_labels, times, totalP_vals )
totalP.setTitle( "Total Photosynthesis" )
GLOBAL.display( totalP )