R is the difference between the sums of consecutive pairs
I used the diff (x,) function on the dataset to find the difference between the strength for 0.0003s time intervals. The problem stems from such high sampling rates and measurement inaccuracies of the system that it does not provide any meaningful data.
I am wondering if it is possible to find the difference between 100 consecutive numbers. For example, "difference = (Fz101 + Fz102 ... Fz200) - (Fz1 + Fz2 ... Fz100)
I am currently dividing by 0.000333 (sample rate) as I am trying to find the peak value for (delta Fz) / (delta t.)
(max(diff(lift_S8_Intns40_chainno$Fz)))/0.00033333
[1] 40472.2
Take a look at the familiar question whether it helps me to help me. [link to similar question] [1] How to find the difference between the sums of consecutive pairs and triplets in R?
Any help is appreciated, but my skills are not very good at r, so please keep it as simple as possible.
Data structure
structure(list(Time = c(18.31266667, 18.313, 18.31333333, 18.31366667,
18.314, 18.31433333, 18.31466667, 18.315, 18.31533333, 18.31566667,
18.316, 18.31633333, 18.31666667, 18.317, 18.31733333, 18.31766667,
18.318, 18.31833333, 18.31866667, 18.319, 18.31933333, 18.31966667,
18.32, 18.32033333, 18.32066667, 18.321, 18.32133333, 18.32166667,
18.322, 18.32233333, 18.32266667, 18.323, 18.32333333, 18.32366667,
18.324, 18.32433333, 18.32466667, 18.325, 18.32533333, 18.32566667,
18.326, 18.32633333, 18.32666667, 18.327, 18.32733333, 18.32766667,
18.328, 18.32833333, 18.32866667, 18.329, 18.32933333, 18.32966667,
18.33, 18.33033333, 18.33066667, 18.331, 18.33133333, 18.33166667,
18.332, 18.33233333, 18.33266667, 18.333, 18.33333333, 18.33366667,
18.334, 18.33433333, 18.33466667, 18.335, 18.33533333, 18.33566667,
18.336, 18.33633333, 18.33666667, 18.337, 18.33733333, 18.33766667,
18.338, 18.33833333, 18.33866667, 18.339, 18.33933333, 18.33966667,
18.34, 18.34033333, 18.34066667, 18.341, 18.34133333, 18.34166667,
18.342, 18.34233333, 18.34266667, 18.343, 18.34333333, 18.34366667,
18.344, 18.34433333, 18.34466667, 18.345, 18.34533333, 18.34566667,
18.346, 18.34633333, 18.34666667, 18.347, 18.34733333, 18.34766667,
18.348, 18.34833333, 18.34866667, 18.349, 18.34933333, 18.34966667,
18.35, 18.35033333, 18.35066667, 18.351, 18.35133333, 18.35166667,
18.352, 18.35233333, 18.35266667, 18.353, 18.35333333, 18.35366667,
18.354, 18.35433333, 18.35466667, 18.355, 18.35533333, 18.35566667,
18.356, 18.35633333, 18.35666667, 18.357, 18.35733333, 18.35766667,
18.358, 18.35833333, 18.35866667, 18.359, 18.35933333, 18.35966667,
18.36, 18.36033333, 18.36066667, 18.361, 18.36133333, 18.36166667,
18.362, 18.36233333, 18.36266667, 18.363, 18.36333333, 18.36366667,
18.364, 18.36433333, 18.36466667, 18.365, 18.36533333, 18.36566667,
18.366, 18.36633333, 18.36666667, 18.367, 18.36733333, 18.36766667,
18.368, 18.36833333, 18.36866667, 18.369, 18.36933333, 18.36966667,
18.37, 18.37033333, 18.37066667, 18.371, 18.37133333, 18.37166667,
18.372, 18.37233333, 18.37266667, 18.373, 18.37333333, 18.37366667,
18.374, 18.37433333, 18.37466667, 18.375, 18.37533333, 18.37566667,
18.376, 18.37633333, 18.37666667, 18.377, 18.37733333, 18.37766667,
18.378, 18.37833333, 18.37866667, 18.379), Fz = c(2751.996392,
2751.614101, 2752.364284, 2751.993635, 2751.615723, 2751.995127,
2751.989063, 2751.241442, 2749.366648, 2750.486962, 2748.242022,
2747.498762, 2748.245589, 2747.4998, 2748.254604, 2748.631317,
2749.006798, 2750.129349, 2749.38176, 2749.385262, 2748.640657,
2750.13658, 2748.640073, 2749.393888, 2750.145076, 2751.274421,
2750.157172, 2750.15688, 2750.165279, 2752.407479, 2752.042472,
2753.550297, 2752.424309, 2750.927558, 2751.688556, 2751.317583,
2752.819117, 2752.45398, 2752.836757, 2752.472626, 2754.353062,
2754.725527, 2755.111158, 2754.376021, 2752.882448, 2752.510924,
2754.006329, 2755.508722, 2756.638796, 2756.636202, 2757.76947,
2756.284199, 2757.408096, 2758.165381, 2757.418894, 2758.172774,
2758.178838, 2758.936415, 2758.56421, 2757.448825, 2757.824079,
2758.569203, 2759.69824, 2760.082914, 2759.711827, 2760.840004,
2761.215128, 2760.84743, 2760.099193, 2760.851808, 2759.359468,
2758.25031, 2758.624201, 2759.755281, 2760.511577, 2761.635327,
2763.137948, 2763.143331, 2761.64191, 2763.1528, 2762.406524,
2763.525491, 2763.157339, 2762.781356, 2763.909695, 2764.666851,
2763.919813, 2763.543975, 2763.928017, 2765.045866, 2765.426243,
2766.182961, 2765.058383, 2763.936351, 2765.06542, 2763.947052,
2764.699019, 2764.70424, 2763.584867, 2763.22145, 2763.975492,
2764.349189, 2764.354994, 2763.613307, 2760.9942, 2759.878475,
2762.486297, 2762.115389, 2763.994527, 2762.121615, 2762.876597,
2761.391148, 2761.391991, 2761.768055, 2761.769126, 2759.525662,
2758.406516, 2758.786634, 2758.783261, 2757.669758, 2756.920758,
2756.540737, 2756.545277, 2756.176055, 2756.171515, 2755.423667,
2754.67611, 2753.178257, 2752.423923, 2753.16895, 2748.678277,
2747.927494, 2746.429754, 2746.424955, 2746.797971, 2746.424663,
2745.674982, 2746.424792, 2743.432215, 2743.432994, 2741.179315,
2742.67553, 2739.672447, 2738.921647, 2738.173637, 2737.424005,
2736.294822, 2735.180735, 2734.431882, 2734.425007, 2733.301013,
2732.930623, 2730.676264, 2729.172881, 2728.424855, 2727.298218,
2726.930066, 2726.177678, 2724.680797, 2723.5587, 2723.931652,
2722.428675, 2721.683421, 2720.557108, 2718.311893, 2716.438883,
2717.549484, 2717.545139, 2718.671354, 2714.548217, 2716.42254,
2713.060416, 2714.557005, 2714.554119, 2712.681174, 2711.561898,
2710.437904, 2710.438585, 2709.688272, 2707.067122, 2708.192203,
2705.564778, 2707.439879, 2705.949079, 2705.573079, 2705.577036,
2704.828393, 2702.954102, 2702.20199, 2701.079406, 2699.206235,
2697.708138, 2695.836101, 2696.588814, 2696.968721, 2696.966354,
2696.970764, 2696.22504, 2694.349549, 2695.852121)), .Names = c("Time",
"Fz"), row.names = 1299:1498, class = "data.frame")
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Here's a possible approach using the package zoo
Function
library(zoo)
IntrvalsDif <- function(x, n) {
temp <- rollsum(x, n)
sapply(seq_len(length(x) - n + 1), function(x) temp[x + n] - temp[x])
}
Test
IntrvalsDif(df$Fz, 20)
# [1] 22.712120 31.780260 37.846728 48.042024 55.623904 59.831923 61.789132 67.470180 73.906584 79.581470
# [11] 81.889676 83.816224 80.498591 81.303658 85.113723 87.410109 91.579034 93.126436 97.284240 99.556696
# [21] 101.445531 99.204143 98.458872 96.574869 97.299629 101.391636 108.484213 111.843855 111.830721 108.817601
# [31] 108.804484 104.667484 103.899693 100.132011 94.484088 91.846433 88.453795 88.053184 85.777665 83.127912
# [41] 83.855688 84.967116 86.079728 84.951745 81.943294 79.311783 74.809550 70.305436 67.663273 68.031700
# [51] 68.010152 72.486929 78.453469 83.671546 86.262716 87.723876 86.573048 83.175009 80.529002 79.394259
# [61] 73.758934 70.745457 66.612867 64.351423 62.484932 55.371569 46.756346 42.618145 38.493014 34.730700
# [71] 27.612391 18.995970 6.271506 -3.829068 -10.178434 -18.028571 -24.761686 -32.615260 -40.093775 -46.838338
# [81] -52.458680 -61.082382 -69.714532 -78.721904 -86.991107 -88.898297 -88.564729 -94.941400 -102.449946 -114.087060
# [91] -120.115474 -131.764148 -140.435989 -151.731834 -164.906638 -176.581499 -185.261108 -191.700139 -198.144375 -208.693815
# [101] -217.378887 -226.065596 -232.122351 -241.185464 -251.002620 -264.177813 -277.722667 -288.293768 -297.354158 -303.775595
# [111] -313.566873 -314.745817 -316.279034 -317.070287 -318.979261 -322.381222 -328.406668 -334.420050 -342.305322 -345.705694
# [121] -351.343224 -352.849444 -359.231092 -360.347288 -361.457419 -363.321285 -366.306745 -366.670795 -366.308869 -364.077356
# [131] -365.210203 -366.711412 -371.584748 -371.950517 -369.317205 -366.687770 -363.297645 -361.044891 -356.536870 -352.777977
# [141] -349.395261 -347.887047 -344.504089 -340.758605 -337.002095 -329.879165 -319.755890 -313.731643 -310.687084 -311.395920
# [151] -304.987941 -305.325773 -300.807844 -303.409489 -306.756032 -306.724804 -305.584028 -302.559006 -301.033458 -301.379656
# [161] -296.103079 NA NA NA NA NA NA NA NA NA
# [171] NA NA NA NA NA NA NA NA NA NA
# [181] NA
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