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Monte Caro Simulation, Credit loss, exposure calculations and graphs added

main
Asitav Sen 3 years ago
parent
commit
caf6f0a8d8
  1. 4
      .Rproj.user/178A6739/sources/prop/A1AE5A83
  2. 8
      .Rproj.user/178A6739/sources/session-99529da2/FE6BB309
  3. 2
      .Rproj.user/178A6739/sources/session-99529da2/FE6BB309-contents
  4. 2
      app.R
  5. 298
      forplumber.R

4
.Rproj.user/178A6739/sources/prop/A1AE5A83

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.Rproj.user/178A6739/sources/session-99529da2/FE6BB309-contents

@ -23,7 +23,7 @@ options(shiny.reactlog = TRUE, appDir = getwd())
source("mod_basic.R")
source("panel.R")
source("secretary.R")
# source("forplumber.R")
source("forplumber.R")
source("modals.R")
# Adding initial data

2
app.R

@ -23,7 +23,7 @@ options(shiny.reactlog = TRUE, appDir = getwd())
source("mod_basic.R")
source("panel.R")
source("secretary.R")
# source("forplumber.R")
source("forplumber.R")
source("modals.R")
# Adding initial data

298
forplumber.R

@ -0,0 +1,298 @@
# function to select model
model_sel <- function(dff) {
withProgress(message = "Testing",
detail = "your patience!",
value = 0,
{
setProgress(value = 1, message = "Formatting Data")
df <- dff %>%
dplyr::select(!where(is.Date))
# Removing columns that have only one value
df <- df %>%
select(-names(which(apply(
df, 2, lenun
) == 1)))
df$asset_type <- as.factor(df$asset_type)
#df$supplier <- as.factor(df$supplier)
df$customer_type <-
as.factor(df$customer_type)
print("1")
setProgress(value = 2, message = "Creating initial formula")
# some cleaning
variables <-
colnames(df)[!colnames(df) %in% c("id", "age_of_asset_months", "loan_status")]
form <-
as.formula(paste0(
"Surv(age_of_asset_months, loan_status) ~",
paste(variables, collapse = "+")
))
surv.res <- coxph(form, data = df, id = id)
res <-
as.data.frame(summary(surv.res)$coefficients)
selvars <-
res %>%
filter(is.finite(`Pr(>|z|)`)) %>%
filter(is.finite(z)) %>%
rownames()
for (j in 1:length(variables)) {
selvars[grep(pattern = variables[j], selvars)] <- variables[j]
}
selvars <- unique(selvars)
form <-
as.formula(paste0(
"Surv(age_of_asset_months, loan_status) ~",
paste(selvars, collapse = "+")
))
setProgress(value = 3, message = "Are you still not annoyed?")
scores <- rep(NA, 5)
variables <- selvars
a <- length(variables)
f <- vector(mode = "list", length = a)
scores = vector(length = a)
setProgress(value = 4, message = "No way! Are you still waiting?")
for (i in 1:a) {
v <- variables[i:a]
#n<-paste0("form",i)
f[[i]] <-
coxph(
as.formula(
paste0(
"Surv(age_of_asset_months, loan_status) ~",
paste(v, collapse = "+")
)
),
data = df,
id = id,
x = T,
y = T
)
perror <-
pec(
object = f[[i]],
formula = form,
splitMethod = "cvK5",
data = df
)
scores[i] <-
1 - ibs(perror)["coxph",] / ibs(perror)["Reference",]
}
setProgress(value = 5, message = "Ok. I give up. You win!")
final.model <-
f[[which(scores == max(scores, na.rm = T))]]
setProgress(value = 6, message = "Ha ha! Not so fast!")
})
final.model
}
# function to creadte the predicted table
predic_t<- function(dff,gdpfor,prfor,maxdate, final.model) {
withProgress(message = "Still working",
detail = "Yes, I'm slow :(",
value = 0,
{
setProgress(value = 1, message = "Formatting")
df <- dff %>%
dplyr::select(!where(is.Date))
df$asset_type <- as.factor(df$asset_type)
df$customer_type <-
as.factor(df$customer_type)
gdp.forecast <-
as.data.frame(gdpfor) %>%
mutate(qtr = rownames(.)) %>%
mutate(stringr::str_replace(qtr, " ", "-"))
pats.forecast <-
as.data.frame(prfor) %>%
mutate(qtr = rownames(.)) %>%
mutate(stringr::str_replace(qtr, " ", "-"))
setProgress(value = 2, message = "But need to run some calculations")
z <-
df %>%
group_by(id) %>%
slice_max(age_of_asset_months, n = 1) %>%
ungroup() %>%
#emi = loan balance by number of months left (may not always be the case)
mutate(emi = balance / (loan_tenure_months -
age_of_asset_months)) %>%
mutate(balance.original = balance) %>%
mutate(age.original = age_of_asset_months) %>%
mutate(risk_current = 1 - exp(
-predict(
final.model,
.,
type = "expected",
collapse = id
)
)) %>%
mutate(balance = balance - emi * 12) %>%
mutate(age_of_asset_months = age_of_asset_months +
12) %>%
# lag of macroeconomic forecasts used because effect of economy should reflect later in loan performance
mutate(
gdp_lag = gdp.forecast[gdp.forecast$qtr == zoo::as.yearqtr(maxdate + months(11)),]$`Point Forecast`,
prices_lag = pats.forecast[pats.forecast$qtr ==
zoo::as.yearqtr(maxdate + months(11)),]$`Point Forecast`
) %>%
mutate(risk_1yr = 1 - exp(
-predict(
final.model,
.,
type = "expected",
collapse = id
)
)) %>%
mutate(balance = balance - emi * 12) %>%
mutate(age_of_asset_months = age_of_asset_months +
12) %>%
mutate(
gdp_lag = gdp.forecast[gdp.forecast$qtr == zoo::as.yearqtr(maxdate + months(23)),]$`Point Forecast`,
prices_lag = pats.forecast[pats.forecast$qtr ==
zoo::as.yearqtr(maxdate + months(23)),]$`Point Forecast`
) %>%
mutate(risk_2yr = 1 - exp(
-predict(
final.model,
.,
type = "expected",
collapse = id
)
)) %>%
mutate(balance = balance - emi * 12) %>%
mutate(age_of_asset_months = age_of_asset_months +
12) %>%
mutate(
gdp_lag = gdp.forecast[gdp.forecast$qtr == zoo::as.yearqtr(maxdate + months(35)),]$`Point Forecast`,
prices_lag = pats.forecast[pats.forecast$qtr ==
zoo::as.yearqtr(maxdate + months(35)),]$`Point Forecast`
) %>%
mutate(risk_3yr = 1 - exp(
-predict(
final.model,
.,
type = "expected",
collapse = id
)
)) %>%
mutate(balance = balance - emi * 12) %>%
mutate(age_of_asset_months = age_of_asset_months +
12) %>%
mutate(
gdp_lag = gdp.forecast[gdp.forecast$qtr == zoo::as.yearqtr(maxdate + months(47)),]$`Point Forecast`,
prices_lag = pats.forecast[pats.forecast$qtr ==
zoo::as.yearqtr(maxdate + months(47)),]$`Point Forecast`
) %>%
mutate(risk_4yr = 1 - exp(
-predict(
final.model,
.,
type = "expected",
collapse = id
)
)) %>%
mutate(balance = balance - emi * 12) %>%
mutate(age_of_asset_months = age_of_asset_months +
12) %>%
mutate(
gdp_lag = gdp.forecast[gdp.forecast$qtr == zoo::as.yearqtr(maxdate + months(59)),]$`Point Forecast`,
prices_lag = pats.forecast[pats.forecast$qtr ==
zoo::as.yearqtr(maxdate + months(59)),]$`Point Forecast`
) %>%
mutate(risk_5yr = 1 - exp(
-predict(
final.model,
.,
type = "expected",
collapse = id
)
)) %>%
group_by(id) %>%
tidyr::pivot_longer(
cols = c(
"risk_current",
"risk_1yr",
"risk_2yr",
"risk_3yr",
"risk_4yr",
"risk_5yr"
)
) %>%
mutate(r_n = row_number()) %>%
mutate(t.emi = emi + emi * 12 * (r_n - 1)) %>%
mutate(balance = ifelse(t.emi == max(emi), balance, balance -
t.emi)) %>%
mutate(balance = ifelse(balance <= 0, 0, balance)) %>%
filter(t.emi > 0)
setProgress(value = 3, message = "At last. Now wait for the plot please.")
})
z
}
# function to process simulated data
# supporting function
sim_fin_supp<-function(simdata, name.fil="risk_current"){
simdata %>%
filter(name == name.fil) %>%
ungroup() %>%
select(matches("sim?")) %>%
colSums()
}
#main function
sim_fin<- function(simdata){
dtc <- sim_fin_supp(simdata,"risk_current")
dt1 <- sim_fin_supp(simdata,"risk_1yr")
dt2 <- sim_fin_supp(simdata,"risk_2yr")
dt3 <- sim_fin_supp(simdata,"risk_3yr")
dt4 <- sim_fin_supp(simdata,"risk_4yr")
dt5 <- sim_fin_supp(simdata,"risk_5yr")
# creating density
hisc <- density(dtc)
his1 <- density(dt1)
his2 <- density(dt2)
his3 <- density(dt3)
his4 <- density(dt4)
his5 <- density(dt5)
# data frame from density
dtc <- data.frame(x = hisc$x, y = hisc$y)
dtc$r <- rep("risk_0yr", times = nrow(dtc))
dt1 <- data.frame(x = his1$x, y = his1$y)
dt1$r <- rep("risk_1yr", times = nrow(dt1))
dt2 <- data.frame(x = his2$x, y = his2$y)
dt2$r <- rep("risk_2yr", times = nrow(dt2))
dt3 <- data.frame(x = his3$x, y = his3$y)
dt3$r <- rep("risk_3yr", times = nrow(dt3))
dt4 <- data.frame(x = his4$x, y = his4$y)
dt4$r <- rep("risk_4yr", times = nrow(dt4))
dt5 <- data.frame(x = his5$x, y = his5$y)
dt5$r <- rep("risk_5yr", times = nrow(dt5))
df <- rbind(dtc, dt1, dt2, dt3, dt4, dt5)
return(df)
}
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